THE
THEORY AND PRACTICE
OF
BREWING.

BY MICHAEL COMBRUNE, Brewer.

ORIGINALLY PUBLISHED WITH PERMISSION OF THE MASTER, WARDENS,
AND COURT OF ASSISTANTS OF THE WORSHIPFUL
COMPANY OF BREWERS.

A NEW EDITION.
CORRECTED AND GREATLY ENLARGED BY THE AUTHOR.

LONDON:
PRINTED FOR VERNOR AND HOOD, LONGMAN AND REES, CUTRELL
AND MARTIN, AND J. WALKER,
By J. Wright, St. John’s Square, Clerkenwell.
1804.

TO
DOCTOR PETER SHAW,
PHYSICIAN TO HIS MAJESTY,
FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON,
AND OF THE ROYAL SOCIETY.

Sir,

The brewing of malt liquors has hitherto been conducted by such vague traditional maxims, that an attempt to establish its practice on truer and more fixed principles must, like every new essay, be attended with difficulties.

Your works, Sir, will be lasting monuments, not only of your great abilities, but also of your zeal for the improvement of the arts, manufactures, and commerce of your country. You will therefore permit me to place under your patronage this treatise, which, if it can boast no other merit, has that of having been undertaken and finished by your advice and counsel.

Some favor, I hope, will be shewn for this distant endeavour to imitate the laudable example you have set, and whatever be the success, I shall ever glory in the opportunity it has given me of professing myself publicly,

Sir,

Your most obedient,

And most obliged humble Servant,

Michael Combrune.

Hampstead, Middlesex,
December 15, 1761.

THE
CONTENTS.

THE
PREFACE.

The difference that appears in the several processes of brewing, though executed with the same materials, by the same persons, and to the same intent, is generally acknowledged. The uneasiness this must occasion to those who are charged with the directive part of the business, cannot be small: and the more desirous they are of well executing the duty incumbent on them, the greater is their disappointment, when frustrated in their hopes. To remove this uncertainty, no method seems preferable to that of experiments, as it is by this means alone, any art whatever can be established upon a solid foundation: but these require caution, perseverance, and expence; they must be multiplied and varied both for the same and for different purposes. The operations of nature elude superficial enquiries, where we have few or no principles for our guides, many experiments are made, which tend only to confound or deceive. Effects seen, without a sufficient knowledge of their causes, often are neglected, or viewed in an improper light, seldom faithfully reported, and, for want of distinguishing the several circumstances that attend them, many times become the support of old prejudices, or the foundation of new ones.

Whoever is attentive to the practical part of brewing, will soon be convinced that heat, or fire, is the principal agent therein, as this element, used in a greater or less degree, or differently applied, is the occasion of the greatest part of the variety we perceive. It is but a few years since the thermometer has been found to be an instrument sufficiently accurate for any purposes where the measure of heat is required. And, as it is the only one with which we are enabled to examine the processes of brewing, and to account for the difference in the effects, a theory of the art, founded on practice, must be of later date than the discovery of the instrument that guides us to the principles.

So long since as the year 1741, I began this research, and never neglected any opportunity to consult the artists of the trade, or to try such experiments as I conceived might be conducive to the purpose. It is needless, perhaps shameful, to mention their number, or to speak of the many disappointments I met with in this pursuit. Error admits of numberless combinations. Truth alone is simple, and confirmed by continuity. At last, flattering myself with having collected the true theory, assisted and encouraged by men of abilities, I thought it fit the public should judge whether I had succeeded in my endeavours; and in 1758 the Essay on Brewing was submitted to them, either for their approbation, or that the errors therein might be pointed out. I have had no reason to repent of my temerity, though perhaps the novelty, more than the merit of this performance, engaged the attention, I may add the favor and advice of some good judges. They have allowed my principles to be at least plausible, and their agreement with practice has since repeatedly convinced me they were not far from truth.

The Essay just mentioned, revised and corrected, naturally forms the first part or theory of the present treatise. The second part is entirely practical. After giving a short idea of the whole process, I resume its different branches in as many chapters, and endeavour in such manner to guide the practitioner, that he may, in every part, at all times, and under a variety of circumstances, know what he is to do, and seldom, if ever, to be disappointed in his object.

From the investigation of so extensive a business, some benefit, it is hoped, must accrue to the public; from the process of brewing being carried on in a just and uniform manner, our malt liquors, probably, will in time better deserve the name of wine.

Boerhaave, Shaw, Macquer, and most of the great masters in chymistry are far from limiting that name to the liquors produced from the juice of the grape: they extend it to all fermented vegetable juices, which, on distillation, yield an ardent spirit, and look on the strength and faculty wine has to cherish nature, and preserve itself, to be in proportion to the quantity it possesses of this liquid, generally termed spirit of wine. This, when thoroughly pure and dephlegmated, is one and the same, whatever different vegetable it is produced from. Barley wines possess the same spiritous principle, which is the preservative part of the most valuable foreign wines, with a power of being brewed superior or inferior to them in quality, and the other constituent parts of beer, beside this ardent spirit, will not, I believe, be esteemed less wholesome than those which make up the whole of grape wine.

The reasons why Great Britain hath not hitherto furnished foreign nations with this part of her product, but more especially her seamen, are obvious. Our mariners, when at home, do not dislike beer, either as to their palates, or its effects on their constitution; but when abroad, spiritous liquors, or new wines, often the product of an enemy’s country, are substituted in lieu thereof. The disuse of beers, on these occasions, has been owing to the uncertainty of the principles on which they were brewed; the maintaining them sound in long voyages and in hot climates, could not sufficiently be depended upon; and it has been supposed they could not be procured at so easy a rate as wines, brandies, or rums, purchased abroad. The first of these objections, the author hopes, by this work, to remove; and, were all the duties to be allowed on what would be brewed for this purpose, our seamen might be furnished with beer stronger than Spanish wine, and at a less expence, the mean price of malt and hops being taken for seven years. It is true that, in times of peace, the seamen in his Majesty’s service are not very numerous, but the number of those then employed by merchants is considerable. I should not have presumed to mention this, but on account of the encouragement given to the exportation of corn, and to many manufactures of British growth or British labor. It is computed that, in England and Wales, are brewed three millions five hundred thousand quarters of malt yearly, for which purpose upwards of one hundred and fifty thousand weight of hops are used. The improvement of the brewery might become a means of increasing the consumption of the growth of our country, viz. of barley, to more than one hundred thousand quarters, and of hops to between fourteen and fifteen thousand weight annually.

Whether this be an object deserving the attention of the legislative power, or of the landed interest, and what might be the proper means to put it successfully in practice, are considerations which do not belong to this place; it being sufficient here to point out, how universally beneficial it is to establish the art of brewing on true and invariable principles.

This being the first attempt, that has been made, to reduce this art to rules and principles, the Author hopes he has a just claim to the indulgence of the public, for any errors he unwillingly may have adopted; far from believing that there is no room left for future improvements, he recommends it to those, who, blessed with superior talents and more leisure than himself, may be inclined to try their skill in the same field, to watch closely the steps of Nature; after the strictest enquiry made, it will be found, the success of brewing beers and ales wholly depends on a true imitation of the wines she forms.

This second edition, it may be observed, in many respects, differs considerably from the first. I have endeavoured to convert to use every advice, every opinion I received, and having put these to the test of farther practice, flatter myself it will be found improved.

A COPY OF DOCTOR SHAW’S LETTER.

ON PERUSING THE ESSAY BEFORE MENTIONED.

Dear Sir,

I HAVE, with pleasure and improvement, read over your manuscript; and should be glad to see some other trades as justly reduced to rules as you have done that of brewing: which would not only be making a right application of philosophical knowledge, but, at the same time, accommodate human life, in many respects, wherein it is still deficient. Perhaps your example may excite some able men, to give us their respective trades, in the form of so many arts. For my own part, having long wished to see some attempts of this kind, for the good of society in general, I cannot but be particularly pleased with the nature, design, and execution of your essay, and am,

Dear Sir,

Your obliged Friend,

And humble Servant,

PETER SHAW.

Pall-Mall, July 20,
1758.

AN
EXPLANATION
OF THE
TECHNICAL TERMS.

The intent of every brewer, when he forms his drink, is to extract the fermentable parts of the malt, in the most perfect manner; to add hops, in such proportion as experience teaches him will preserve and ameliorate the beer; and to employ just so much yeast as is sufficient to obtain a complete fermentation.

Perhaps it may be said, these particulars are already sufficiently understood, and that it would be a much more useful work to publish remedies for the imperfections, or diseases, beer is naturally or accidentally subject to, and which at present are deemed incurable. But if the designs just now mentioned be executed according to the rules of chymistry, such imperfections and such diseases not existing, the remedies will not be wanted; for beer brewed upon true principles, is, neither naturally nor accidentally, subject to many disorders often perceived in it. Hence it is evident, that some knowledge of chymistry is absolutely necessary to complete the brewer, as, without the informations acquired from that science, he must be unqualified to lay down rules for his practice, and to secure to himself the favor of the public; for which purpose, and to make this treatise useful to those concerned in the practical part of brewing, it has been thought adviseable to avoid, as much as possible, the technical terms of art, to prefix an explanation of those that necessarily occur, and, in as short a manner as possible, to trace the properties of fire, air, water, and earth, as far as they relate to the subject.

Acids are all those things which taste sour, as vinegar, juice of lemons, spirit of nitre, spirit of salt, the oil and spirit of vitriol, &c. and are put in a violent agitation, by being mixed with certain earths, or the ashes of vegetables. An acid enters, more or less, into the composition of all plants, and is produced by, or rather is the last effect of, fermentation. Mixed in a due proportion with an alkali, it constitutes a neutral salt, that is, a salt wherein neither the acid nor alkali prevail. Acids are frequently termed acid salts, though generally they appear under a fluid form.

Alkalies, or alkaline salts, are of a nature directly contrary to the acids, and generally manifest themselves by effervescing therewith: they have an urinous taste, and are produced from the ashes of vegetables, and by several other means. They, as well as testaceous and calcarious substances, are frequently made use of by coopers, to absorb the acid parts of stale beer, by them called softning.

Air is a thin elastic fluid, surrounding the globe of the earth; it is absolutely necessary to the preservation both of animal and vegetable life, and for the exciting and carrying on fermentation.

Alcohol is the pure spirit of wine, generally supposed to be without the least particle of water or phlegm.

Animals are organized bodies, endued with sensation and life. Minerals are said to grow and increase, plants to grow and live, but animals only to have sensation.—Animal substances cannot ferment so as to produce by themselves a vinous liquor; but there may be cases wherein some of their parts rather help than retard the act of fermentation.[1]

Atmosphere is that vast collection of air, with which the earth is surrounded to a considerable height.

Attraction is an indefinite term, applicable to all actions whereby bodies tend towards one another, whether by virtue of their weight, magnetism, electricity, or any other power. It is not, therefore, the cause determining some bodies to approach one another, that is expressed by the word attraction, but the effect itself. The space, through which this power extends, is called the sphere of attraction.

Blacking is a technical term used by coopers, to denote sugar that is calcined, until it obtains the colour that occasions the name.

Brewing is the operation of preparing beers and ales from malt.

Boiling may thus be accounted for. The minute particles of fuel being by fire detached from each other, and becoming themselves fire, pass through the pores of the vessel, and mix with the fluid. These, being perpetually in an active state, communicate their motion to the water: hence arises, at first, a small intestine motion, and from a continued action in the first cause, the effect is increased, and the motion of the liquor continually accelerated; by degrees, it becomes sensibly agitated, but the particles of the fire, acting chiefly on the particles that compose the lowest surface of the water, give them an impulse upwards, by rendering them specifically lighter, so as to determine them to ascend, according to the laws of equilibrium. Hence there is a constant flux of water from the bottom to the top of the vessel, and reciprocally from the top to the bottom. This appears to be the reason why water is hot at the top sooner than at the bottom, and why an equal heat cannot be distributed through the whole. The thermometer therefore can be of little service, to determine immediately the degree of heat, especially in large vessels, on which account it is better for brewers to heat a certain quantity just to the act of boiling, and to temper it, by adding a sufficient quantity of cold water. Boiling water is incapable of receiving any increase of heat, though acted on by ever so great a fire, unless the atmosphere becomes heavier, or the vapours of the water be confined. It occasions the mercury to rise, according to Farenheit’s scale, to 212 degrees.

Charr. A body is said to be charred when, by fire, its volatile or most active parts are drove out; its coarse oils, by the same means, placed chiefly on the external parts; and so deprived of color as to be quite black.

Cleansing is the act of removing the beer from the ton, where it was first fermented, into the casks.

Cloudy is an epithet joined to such beers, which, from the violent heat given to the water that brewed them, are loaded with more oils than can be attenuated by fermentation, and incorporated with the water; from whence a muddy and grey oil is seen floating on the surface of the liquor, though the body is often transparent; this oil is frequently extracted in such quantity as to exceed the power of any known menstruum.

Cohesion is that action by which the particles of the same body adhere together, as if they were but one.

Cold is a relative term in opposition to heat. Its greatest degree is not known, and it is supposed that the colder a body is, the less is the agitation of its internal parts.

Colour; a greater or less degree of heat causes different colours in most bodies, and from a due observation of the colour of malt, we may determine what degree of heat it has been impressed with.

Density expresses the closeness, compactness, or near approach of the parts of a body to one another: the more a body weighs in proportion to its bulk, the greater is its density. Gold is the densest body in nature, because there is none known of the same bulk, which weighs so much.

Earth is that fossil matter or element, whereof our globe partly consists.

Ebullition is the boiling or bubbling of water, or any other liquor, when the fire has forced itself a passage through it. Brewers suppose water to be just beginning to boil, when they perceive a small portion of it forced from the bottom upwards in a right line, so as to disturb the surface: when the liquor is in this state, they call it through, or upon the point of ebullition. The vulgar notion that the water is hotter at this time than when it boils, is without any foundation.

Effervescence is a sudden agitation, arising in certain bodies upon mixing them together; this agitation most commonly generates heat.

Elasticity, or springiness, is that property of bodies, by which they restore themselves to their former figure, after any pressure or distension.

Expansion is the swelling or increase of the bulk of bodies from heat, or any other cause.

Extract consists of the parts of a body separated from the rest, by cold or hot water.

Fermentation is a sensible internal motion of the particles of a mixture: by the continuance of this motion, the particles are gradually removed from their former situation, and, after some visible separation, joined together again in a different order and arrangement, so as to constitute a new compound. No liquors are capable of inebriating, except those that have been fermented.

Fixed Bodies are those, which, consisting of grosser parts, cohering by a strong attraction, and by that means less susceptible of agitation, can neither be separated nor raised, without a strong heat, or perhaps not without fermentation.

Fire is only known by its properties, of which the chief are to penetrate and dilate all solid and fluid bodies.

Freezing Point is the degree of cold, at which water begins to be formed into ice, which, according to Farenheit’s scale, is expressed by 32.

Foxed is a technical term, used by brewers, to indicate beers in a putrid state.

Gums are concreted vegetable juices, which transude through the bark of certain trees, and harden upon the surface; they easily dissolve in water, and by that means distinguish themselves from balsams or resins.

Hermetically Sealed is a particular method of stopping the mouth of vessels, so close that the most subtil spirit cannot fly out, which is done by heating the neck of the bottles, till it is just ready to melt, and then with hot pinchers twisting it close together.

Homogeneous is an appellation given to such parts or subjects, which are similar or of the same nature and properties.

Isinglass is a preparation from a fish called huso, somewhat bigger than the sturgeon; a solution of which in stale beer is used, to fine or precipitate other beers: it is imported from Russia by the Dutch, and from them to us.

Light consists of particles of matter inconceivably small, capable of exciting in us the sensation of colours, by being reflected from every point of the surface of luminous bodies; but, notwithstanding they are so exceeding small, Sir Isaac Newton found means to divide a single ray into seven distinct parts, viz. red, orange, yellow, green, blue, indigo, and violet.

Malt, in general, is any sort of grain, first germinated, and then dried, so as to prevent any future vegetation: that generally used, is made of barley, which experience has found to be the fittest for the purpose of brewing.

Medium is that space, through which a body in motion passes: air is the medium through which the bodies near the earth move; water is the medium wherein fish live; glass affords a medium or a free passage to light.—This term is also made use of, to express the mean of two numbers, and sometimes the middle between several quantities.

Musts are the unfermented juices of grapes, or of any other vegetable substances.

Menstruum is any fluid, which is capable of interposing its parts between those of other bodies, and in this manner either dissolves them perfectly, or extracts some part of them.

Oil is an unctuous, inflammable substance, drawn from several animal and vegetable substances.

Precipitation. Isinglass dissolved becomes a glutinous and heavy body; this put into malt liquors intended to be fined, carries down, by its weight, all those swimming particles, which prevent its transparency; and this act is called fining, or precipitation.

Repulsion; “Doctor Knight defines it to be that cause which makes bodies mutually endeavour to recede from each other, with different forces at different times.” In this case they are placed beyond the sphere of each other’s attraction or cohesion, and mutually fly from each other.

Resins, or balsams, are the oils of vegetables inspissated and combined with a proportion of the acid salts; as well as they mix with any spirituous liquor, as little are they soluble in water; but they become so, either by the intervention of gums or soaps, or by the attenuating virtue of fermentation.

Salts are substances sharp and pungent, which readily dissolve in water, and from thence, by evaporation, crystallise and appear in a solid form. They easily unite together, and form different compounds. Thus salts, composed of acids and alkalies, partake of both, and are called neutral.

Sett: a grist of malt is by brewers said to be sett, when, instead of separating for extraction, it runs in clods, increases in heat, and coagulates. This accident is owing to the over quantity of fire in the water, applied to any of the extractions. The air included in the grist, which is a principal agent in resolving the malt, being thereby expelled, the mass remains inert, and its parts, adhering too closely together, are with difficulty separated. Though an immediate application of more cold water to the grist is the only remedy, yet, as the cohesion is speedy and strong, it seldom takes effect.—New malts, which have not yet lost the heat they received from the kiln, are most apt to lead the brewer into this error, and generally in the first part of the process.

Sugar, or saccharine salts, are properly those that come from the sugar canes; many plants, fruits and grains give sweet juices reducible to the same form; they are supposed to be acids smoothed over with oils; all vegetable sweets are capable of fermenting spontaneously when crude; if boiled, they require an addition of yeast to make them perform that act. Malt, or its extracts, have all the properties of saccharine salts.

Sulphur. Though by sulphur is commonly understood the mineral substance called brimstone, yet in chymistry it is frequently used to signify in general any oily substance, inflammable by fire, and, without some saline addition, indissoluble in water.

Soap or Saponaceous Juices. Common soap is made of oil mixed with alkaline salts: this mixture causes a froth on being agitated in water. The oils of vegetables are, in some degree, mixed with their salts; and according to the nature of these salts, appear either resinous or saponaceous, that is, soluble or indissoluble in water.— Sugar is a kind of soap, rendering oil miscible with water; and therefore all bodies, from which saccharine salts are extracted, may be termed saponaceous.

Vegetable is a term applied to plants, considered as capable of growth, having vessels and parts for this purpose, but generally supposed to be without sensation.

Vinegar is an acid penetrating liquor, prepared from wine, beer, cyder, or a must, which has been fermented as far as it was capable.

Vitriol is, in general, a metalline substance combined with the strongest acid salt known. This acid, being separated from the metal, differs in nothing from that which is extracted from alum or brimstone. It is improperly called spirit of vitriol, when diluted with water, and, with as little propriety, oil, when free from it.

Volatile Bodies are those, which, either from their smallness or their form, do not cohere very strongly together, and being most susceptible of those agitations, which keep liquors in a fluid state, are most easily separated and rarified into vapour, with a gentle heat, and on the contrary condensed and brought down with cold.

Wine is a brisk, agreeable, spirituous, fluid cordial, formed from fermented vegetable bodies. In this sense beers and ales may be called, and really are, barley wines.

Worts are the unfermented extracts of malt.

Yeast is both the flowers and lees of a fermented wort, the former of these being elastic air enveloped in a subject less strong and less consistent than the latter.

PRINCIPLES
OF THE
THEORY OF BREWING.

SECTION I.
OF FIRE.

Though fire is the chief cause and principle of almost every change in bodies, and though persons untaught in chymistry imagine they understand its nature, yet, certain it is, few subjects are so incomprehensible, or elude so much our nicest research. The senses are very inadequate judges of it; the eye may be deceived, and suppose no fire in a bar of iron, because it does not appear red, though at the same time it may contain enough to generate pain: the touch is equally unfaithful, for a body, containing numberless particles of heat, will to us feel cold, if it is much more so than ourselves.

The great and fundamental difference among philosophers, in respect to the nature of fire, is, whether it be originally such, formed by the Creator himself, at the beginning of things; or whether it be mechanically producible in bodies, by inducing some alteration in the particles thereof. It is certain that heat may be generated in a body, by attrition; but whether it existed there before, or was caused immediately by the motion, is a matter of no great import to the art of brewing; for the effects, with which we are alone concerned, are the same.

Fire expands all bodies, both solid and fluid. If an iron rod just capable of passing through a ring of the same metal, is heated red-hot, it will be increased in length, and so much swelled as not to be able to pass through the ring, as before:[2] if a fluid is put into a bellied glass, with a long slender neck, and properly marked, the fluid, by being heated, will manifestly rise to a considerable height.

The expansion of fluids, by heat, is different in different fluids; with some exceptions, it may be said to be in proportion to their density. Pure rain water, gradually heated to ebullition, is expanded one 26th part of its bulk,[3] so that 27 gallons of boiling water, will, when cold, measure no more than 26, and 27 gallons of boiling wort will not yield so much, because worts contain many oily particles, which, though less dense than water, have the property of being more expansible: hence we see the reason why a copper, containing a given number of barrels of wort, when cold, is not capable to hold the same of beer, when boiling.

Bodies are weakened or loosened in their texture by fire: the hardest, by an increased degree of heat, will liquify and run; and vegetables are resolved and separated by it into their constituent parts. It must be owned vegetables seem at first, on being exposed to the fire, to become rigid or stiff; but this is owing to the evaporation of the aqueous particles, which prevented a closer adhesion of the solid matter. It is only in this manner fire strengthens some bodies which before were weak.

That the texture of bodies should be loosened by fire, seems a consequence of expansion; for a body cannot be expanded but by its particles receding farther from one another; and if these be not able to regain the situation they had when cold, the body will remain looser in its texture than before it suffered the action of fire. This is the case of barley when malted.

Fire may be conveyed through most bodies, as air, water, ashes, sand, &c. The effect seems to be different according to the different conveyances. A difference appears between boiling and roasting, yet they answer the same purpose, that of preserving the subject; and this, in proportion to the degree of heat it has suffered. A similar variety appears, even to our taste, from the different conveyance of fire to malt: for acids having a great tendency to unite with water, if this element does not naturally contain any itself, is the reason why a great heat is conveyed through water, and applied to extract the virtues of pale malt; the water gaining from the grain some of these salts, or possessing them itself, the effect of this great aqueous heat is not to imprint on the palate a nauseous burnt taste, as is the case of great heats, when conveyed through air to the same grain. The salts the water has obtained, or perhaps had, being sheathed by the oils it draws from the malt, rather become saccharine, which cannot be the case when oils are acted upon by a strong heat, entirely void of any such property; but malt, the more it is dried, the longer is it capable of maintaining itself in a sound state, and the liquor brewed with it will, in proportion to its dryness, keep the longer sound, the hotter the water is, applied to malt, provided its heat doth not exceed the highest extracted degree, the more durable and sound will the extract be.

The last consideration of fire or heat, relative to brewing, is the knowledge of its different degrees, and how to regulate them. Till of late, chymists and all others, were much to seek in this respect; they distinguished more or less fire in a very vague and indeterminate manner, as the first, second, third, and fourth degree of heat, meaning no precise heat, or heat measured by any standard; but, by the invention of the thermometer, we are enabled to regulate our fires with the utmost precision. Thermometers are formed on different scales; and therefore, when any degree of heat is mentioned, in order to avoid confusion, the scale made use of should be indicated. I have constantly employed Fahrenheit’s, as it is the most perfect, and the most generally received. According to this instrument,[4] by the author of it, an artificial cold was made so as the mercury stood at 72 divisions below the first frost. The gentlemen of the French Academy, in the winter of the year 1736, observed, at Torneao, Latitude 65° 51´, the natural cold to be 33 degrees below 0: these are proofs there are colds much more intense than the first frost, or 32 degrees, where water first begins to harden into ice; from 32 to 90 degrees are the limits of vegetation, according to the different plants that receive those or the intermediate heats. The 40th degree is marked by Boerhaave as the first fermentable heat, and the 80th as the last: 47 degrees I have found to be generally the medium heat of London, throughout the year, in the shade; 98 degrees is said to be that of our bodies when in health, as from 105 to 112 are its degrees when in a fever. Hay stacked with too much moisture, when turned quite black, in the heart of the rick, indicated a heat of 165 degrees. At 175 the purest and highest-rectified spirits of wine boil, and at this degree I have found well-grown malts to charr, at 212 degrees water boils, at 600 quicksilver and oil of vitriol. Gold, silver, iron, and most other metals in fusion exceed this heat; greater still than any known is the fire in the focus of the burning lens of Tschirnhausen, or of the concave mirror made by Villette; they are said to volatilise metals and vitrify bricks. Thus far experiments have reached; but how much more, or how much less, the power of this element extends, will probably be forever hid from mankind.

SECTION II.
OF AIR.

None of the operations, either of nature or art, can be carried on without the action or assistance of air. It is a principal agent in fermentation; and therefore brewers ought to be well acquainted with its principal properties and powers.

By air we mean a fluid, scarcely perceptible to our senses, and discovering itself only by the resistance it makes to bodies. We find it every where incumbent on the surface of the globe, rising to a considerable height, and commonly known by the name of atmosphere. The weight of air is to that of water as 1 to 850, and its gravitating force equal to that of a column of water of 33 feet high; so that an area of one foot square receives, from air, a pressure equal to 2080 pounds weight.

Elasticity is a property belonging only to this element, and this quality varies in proportion to the compressing weights. We scarcely find this element, (any more than the others) in a pure state; one thousandth part of common air, says Boerhaave, consists of aqueous, spiritous, oily, saline, and other particles scattered through it.—These are not, or but little, compressible, and in general prevent fermentation: consequently, where the air is purest, fermentation is best carried on. The same author suspects, that the ultimate particles of air cohere together, so as not easily to insinuate themselves into the smallest pores, either of solids or fluids. Hence, those acquainted with brewing, easily account, why very hot water, which forces strong and pinguious particles from malt, forms at the same time extracts unfavourable for fermentation, as oils are an obstruction to the free entrance of air; and, from an analogous reason, extracts which are much less impressed with fire, in them fermentation is so much accelerated, that the whole soon becomes sour.

Air, like other bodies, is expanded and rarified by heat, and exerts its elasticity in proportion to the number of degrees of fire it has received; the hotter therefore the season is, the more active and violent will the fermentation be.

Air abounds with water, and is perpetually penetrating and insinuating itself into every thing capable of receiving it. Its weight, or gravitating force, must necessarily produce numberless effects. The water contained in the air is rendered more active by its motion; hence the saline, gummous, and saponaceous particles it meets with are loosened in their texture, and, in some degree, dissolved. As principles similar to these are the chief constituent parts of malt, the reason is obvious why such, which are old, or have lain a proper time exposed to the influence of the air, dissolve more readily, or, in other words, yield a more copious extract than others.

All bodies in a passive state, remaining a sufficient time in the same place, become of the same degree of heat with the air itself. On this account the water, lying in the backs used by brewers, is nearly of the same degree of heat as the thermometer shews the open air in the shade to be. When this instrument indicates a cold below the freezing point, or 32 degrees, if the water does not then become ice, the reason is, because it has not been exposed long enough to be thoroughly affected by such a cold. For water does not immediately assume the same degree of temperature with the air, principally on account of its density, also from its being pumped out of deep and hot wells, from its being kept in motion, and from many other incidents. Under these circumstances, no great error can arise to estimate its heat equal to 35 degrees.

Air is not easily expelled from bodies, either solid or fluid. Water requires two hours boiling to be discharged of the greatest part of its air. That it may be thus expelled by heat appears from hence; water, if boiled the space abovementioned, instead of having any air bubbles when it is froze, as ice commonly has, becomes a solid mass like crystal.

Worts or musts, as they contain great quantities of salts and oils, require a greater degree of heat to make them boil: consequently more air is expelled from boiling worts, than from boiling water in the same time; and as air doth not instantaneously re-enter those bodies,[5] when cold, they would never ferment of themselves. Were it not for the substitute of yeast, to supply the deficiency of air lost by boiling, they would fox or putrify, for want of that internal elastic air, which is absolutely necessary to fermentation.

As air joined to water contributes so powerfully to render that fluid more active, that water which has endured fire the least time, provided it be hot enough, will make the strongest extracts.

Though there is air in every fluid, it differs in quantity in different fluids; so that no rule can be laid down for the quantity of air, which worts should contain.—Probably the quantity, sufficient to saturate one sort, will not be an adequate proportion for another.

Air in this manner encompasses, is in contact with, confines, and compresses all bodies. It insinuates itself into their penetrable passages, exerts all its power either on solids, or fluids, and finding in bodies some elements to which it has a tendency, unites with them. By its weight and perpetual motion, it strongly agitates those parts of the bodies in which it is contained, rubs, and intermixes them intimately together. By disuniting some, and joining others, it produces very singular effects, not easily accomplished by any other means.—That this element has such surprising powers, is evident from the following experiment. “Fermentable parts duly prepared and disposed in the vacuum of Mr. Boyle’s air-pump will not ferment, though acted upon by a proper heat; but, discharging their air, remain unchanged.”

SECTION III.
OF WATER.

As water is perpetually an object of our senses, and made use of for most of the purposes of life, it might be imagined the nature of this element was perfectly understood: but they who have enquired into it with the greatest care, find it very difficult to form a just idea of it. One reason of this difficulty is, water is not easily separated from other bodies, or other bodies from water. Hartshorn, after having been long dried, resists a file more than iron; yet, on distillation, yields much water. I have already observed, that air is intimately mixed with, and possibly never entirely separated from it, but in a vacuum; how is it possible then ever to obtain water perfectly pure?

In its most perfect state, we understand it to be a liquor very fluid, inodorous, insipid, pellucid, and colourless, which, in a certain degree of cold, freezes into a brittle, hard, glassy ice.

Lightness is reckoned a perfection in water, that which weighs less being in general the purest. Hence the great difficulty of determining the standard weight it should have. Fountain, river, or well waters, by their admixture with saline, earthy, sulphureous, and vitriolic substances, are rendered much heavier than in their natural state; on the other hand, an increase of heat, or an addition of air, by varying the expansion, diminishes the weight of water. A pint of rain-water, supposed to be the purest, is said to weigh 15 ounces, 1 drachm, and 50 grains, but, for the reasons just now mentioned, this must differ in proportion as the seasons of the year do from each other.

Another property of water, which it has in common with other liquors, is its fluidity, which is so great, that a very small degree of heat, above the freezing point, makes it evaporate. Experiments to ascertain the proportion steamed away of the quantity of water used in brewing, is an object worthy of the artist’s curiosity; but the purer the water is, the more readily it evaporates. Sea-water, which is supposed to contain one fortieth part of salt, more forcibly resists the power of fire, and wastes much less, than that which is pure.

The ultimate particles of this element, Boerhaave believed to be much less than those of air, as water passes through the pores and interstices of wood, which never transmit the least elastic air; nor is there, says he, any known fluid, (fire excepted, which forces itself through every subject) whose parts are more penetrating than those of water. Yet as water is not an universal dissolver, there are vessels which will contain it, though they will let pass even the thick syrup of sugar, for sugar makes its way by dissolving the tenacious and oily substance of the wood, which water cannot do.

Water, when fully saturated by fire, is said to boil, and by the impulse of that element, comes under a strong ebullition. Just before this violent agitation takes place, I have already observed, it occupies one seventy-sixth more space than when cold: so the brewer who would be exact, when he intends to reduce his liquor to a certain degree of heat, must allow for this expansion, abating therefrom the quantity of steam exhaled.

As water, by boiling, may be said to be filled or saturated with fire, so may it be with any other substance capable of being dissolved therein; but, though it will dissolve only a given quantity of any particular substance, it may, at the same time, take in a certain proportion of some other. Four ounces of pure rain water will melt but one ounce of common salt, and after taking this as the utmost of its quantity, it will still receive two scruples of another kind of salt, viz. nitre. In like manner the strongest extract of malt is capable of receiving the properties belonging to hops: but in a limited proportion. This appears from the thin bitter pelicle, that often swims on the surface of the first wort of brown beers, which commonly are overcharged with hops, by putting the whole quantity of them at first therein; the wort not being capable of suspending all that the heat dissolves, it no sooner cools but these parts rise on the top. This may serve as a hint to prevent this error, by suffering the first wort to have no more hops boiled therein than it can sustain: but as this incident must vary, in proportion to the heat of the extracts and quantity of water used, some few experiments are necessary to indicate the due proportion for the several sorts of drink. This however should always be extended to the utmost, for the first wort, which, from its nature and constituent parts, stands most in need of the preservative quality the hops impart.

Water acts very differently, as a menstruum, according to the quantity of fire it contains: consequently its heat is a point of the utmost importance with regard to brewing, and should be properly varied according to the dryness and nature of the malt, according as it is applied either in the first or last mashes, and in proportion also to the time the beer is intended to be kept. These ends, we hope to shew, are to be obtained to a degree of numerical certitude.

Nutrition cannot be carried on without water, though likely water itself is not the matter of nourishment, but only the vehicle.

Water is as necessary to fermentation as heat or air. The farmer, who stacks his hay or corn before it is sufficiently dried, soon experiences the terrible effects of too much moisture, or water, residing therein: all vegetables therefore intended to be long kept, ought to be well dried. The brewer should carefully avoid purchasing hops that are slack bagged, or kept in a moist place, or malt that has been sprinkled with water soon after it was taken from the kiln. By means of the moisture, an internal agitation is raised in the corn, which agitation, though soon stopped, for want of a sufficient quantity of air, yet, the heat thereby generated remaining, every adventitious seed, fallen from the air, and resting on the corn, begins to grow, and forms a moss, which dies, and leaves a putrid musty taste behind, always prevailing, more or less, in beer made from such grain.

That water is by no means an universal solvent, as some people have believed, has been already observed. It certainly does not act as such on metals, gems, stones, and many other substances: it is not in itself capable of dissolving oils, but is miscible with highly rectified spirits of wine, or alchohol, which is the purest vegetable oil in nature. All saponaceous bodies, whether artificial or natural, fixed or volatile, readily melt therein; and as many parts of the malt are dissoluble in it, they must either be, or become by heat, of the nature of soap, that is, equally miscible with oils and water.

When a saponaceous substance is dissolved in water, it lathers, froths, and bears a head; hence, in extracts of malt, we find these signs in the underback. Weak and slack liquors, which contain the salts of the malt without a sufficient quantity of the oils, yield no froth. Somewhat like this happens, when the water for the extract is over-heated, for then as more oils are extracted than are sufficient to balance the salts, the extract comes down as before, with little or no froth or head. This sameness of appearance, from two causes directly opposite to each other, has many times misled the artist, and shews the necessity there is to employ means less liable to error.

This might be a proper place to observe the difference between rain, spring, river, and pond waters; but as the art of brewing is very little affected by the difference of waters, if they be equally soft, but rather depends on the due regulation of heat; and as soft waters are found in most places, and become more alike, when heated to the degree necessary to form extracts from malt; it is evident, that any sort of beer or ale may be brewed with equal success, where malt and hops can be procured proper for the respective purposes. If hitherto prejudice and interest have appropriated to some places a reputation for particular sort of drinks, it has arose from hence; the principles of the art being totally unknown, the event depended on experience only, and lucky combinations were more frequent where the greatest practice was. Thus, for want of knowing the true reason of the different properties observed in the several drinks, the cause of their excellencies or defects was ignorantly attributed to the water made use of, and the inhabitants of particular places soon found an advantage, in availing themselves of this local reputation. But just and true principles, followed by as just a practice, must render the art more universal, and add dignity to the profession, by establishing the merit of our barley wines on knowledge, not on opinion void of judgment. To place this truth in a fuller light, and to communicate to the brewer the readiest means to examine any waters he may have occasion to use, I have extracted from Doctor Lucas’s Essay on Waters, the experiments he made on the Thames, New River, and Hampstead company’s waters, but without closely adhering to the accuracy this gentleman prescribed to himself; such exactness much better suiting a man of his abilities: for the purposes of brewing it is not of absolute necessity.

Experiments on the Thames, New River, and Hampstead Waters, which in general are in use in the Cities of London and Westminster.

All these waters appear to be sufficiently pure for the common uses of life; the difference between them is very trivial, if any: those of Hampstead approach nearest to the simple state this element is to be wished for. Although it cannot be said to have an immediate relation to this work, yet it may not, perhaps, be disagreeable or useless here to add the quantities of water the cities of London and Westminster, and the adjacent buildings, are daily supplied with.

From the New River Company 57897 Tons per Day.

SECTION IV.
OF EARTH.

Regularity requires some notice should be taken of this element. The great writer on chymistry, so often mentioned, defines it to be a simple, hard, friable, fossil body, fixed in the fire, but not melting in it, nor dissoluble in water, air, alcohol, or oil. These are the characters of pure earth, which, no more than any of the other elements, comes within our reach, free from admixture. Though it is one of the component parts of all vegetables, yet as, designedly, it is never made use of in brewing, except sometimes for the purpose of precipitation; it is unnecessary to say any thing more upon it: whoever desires to be farther informed concerning its properties may consult all, or any of the authors before mentioned.

SECTION V.
OF MENSTRUUMS OR DISSOLVENTS.

By menstruums is understood a body which, in a fluid or subtilised state, is capable of interposing its small parts betwixt the small parts of other bodies. This act so obviously relates to the art of brewing, especially where the extracting of the malt and the boiling of the hops are concerned, that it should not be passed unheeded by.

The doctrine of menstruums, as laid down by Boerhaave, seems most intelligible and applicable to our purpose. He says, the solutions of bodies in general are the effect only of attraction and repulsion, between the particles of the menstruums and those of the body dissolved, the whole action depending on the relation between these two; of consequence, there cannot be any body, natural or artificial, which, without distinction, will dissolve all bodies whatsoever; nor is the cause assignable why certain menstruums dissolve certain bodies: the effects of alcaline, acid, neutral, fixed, or volatile salts, any more than those of oils, water, alcohol, fire, or air, are not to be accounted for by any general rule, that universally holds true; nor even, in many cases, doth the dissolution of a body depend on the purity or simplicity of the menstruum: the nearest path then to success, is cautiously to apply every menstruum we know of to the body whose solvent we want to discover.

The elements of fire and air greatly promote the action and effect of menstruums, and in this light they are admitted as such. Water dissolves most salts, all the natural sapos of plants, and the ripe juices of fruits; for in these, the oils, salts, and spirit of the vegetables, are accurately mixed and concreted together, and malts, having the same constituent parts with them, this element becomes a proper menstruum to extract this grain: though malts, by being dried with heats which greatly exceed what is necessary to bring barley to a state of maturity, do, from hence, require greater, though determinate heats, yet inferior to that at which water boils; but such heats must be applied in proportion to their dryness, to extract their necessary parts. Even earths, by the intervention of acids, dissolve in water; but having treated of the four elements already, as far as we conceived was requisite for the art of brewing, we shall, in this chapter, confine ourselves to oils and salts, and view these acting as menstruums only.

To the definition already given of oils, it may be necessary to add, in general, they contain some water, and a volatile acid salt; that they receive different appellations, and have different properties in proportion to their respective spissitudes. Oils from vegetables are obtained by expression, infusion, and distillation; in either of which methods, a too great heat is to be avoided, as this gives them a prejudicial rancidness, and where water does not interpose, alters their color until thereby they are turned black.

In general oils unite with themselves, but, excepting alcohol, not with water, unless when combined with salts, for salts attract water, and so they do oils: hence arises many elegant preparations both natural and artificial, from which wines are formed.

The power of oils in dissolving bodies is in a proportion to their heat, and being capable, when pure, of receiving a quantity of fire equal to 600 degrees, it is not surprising this liquid should mix with gums and with resinous bodies; but the color of these, and of every subject when thrown into boiling oils, changes in proportion to the impression made on them by heat, either to a yellow, a red, or a black. Oils which are inspissated, or thickened by heat, are termed balsams. Do not the oils of malt, from the heat they have undergone, resemble these? and from the circumstance of their having endured a heat superior to that necessary for putrefaction, may they not be suspected to possess a volatile alcaline salt? Beyond doubt, the extracts from malt (though they boil at a heat of 218 degrees only) yet do they, in great measure, dissolve hops, which are gum resinous.

Salt may well be denominated a menstruum, as it is easily diluted with water; fixed alcaline salts we have already seen appear to be the produce of fire alone.—Such are never distinguished in the composition of vegetables in their natural state; though a volatile alcalious salt (the effect of heat equal or superior to that necessary for putrefaction) is found in many, and especially in such as are putrified.

The power of a fixed alcali as a solvent is great, applied (says Boerhaave) to animal, vegetable, or fossil concretions, so far as they are oils, balsams, gummy, resinous, or of gummy resinous nature, and therefore concreted from oily substances: these, this salt intimately opens, attenuates, and resolves: disposing them to be perfectly miscible with water: oils of alcohol leaving however the impression of taste naturally belonging to this salt.

Vegetable acid salt dissolves animal, vegetable, fossil, and metalline substances, except mercury, silver, and gold. In most terrestrial vegetables this salt is evident; ripe mealy corn has the least indication of it, yet extracts therefrom, when fermented, and sometimes before they are fermented, discover sensibly their acidity. Sea-plants in general have not their roots inserted in the earth at the bottom of the sea, and these in distillation yield an oily volatile alcali; but more subtil than the native acids of vegetables, are the vinous acids produced by fermentation; they dissolve equally most matters put into them, and render the whole homogene. Into a must or wort, when under this act, by means of an elæosaccharum, might be introduced the choicest flavors, and the aromatics of the Indies be applied to heighten the taste and flavor of our barley wines. The laws of England at present subsisting are indeed opposite to any improvement of this sort, from the apprehensions of abuse: but where elegance alone is intended, undoubtedly the merit of our beers and ales might thereby be increased. As such, this is a part of chymical knowledge well worth the enquiry and attention of the brewer.

Neutral salts have already been mentioned; these are very various, and very different when acting as menstruums. Resins and gum-resins are generally said to be most effectually dissolved by alcohol; but Boerhaave informs us, that sal-amoniac (a very salutary subject and a neutral salt) if boiled with gums, resins, or the gum-resins of vegetables, intimately resolves, and disposes them to be conveniently mixed in aqueous and fermenting spiritous menstruums. Of this class of salts thus much is sufficient. This observation perhaps is of too much consequence to escape the notice of the artist.

SECTION VI.
OF THE THERMOMETER.

This instrument is designed for measuring the increase or decrease of heat. By doing it numerically, it fixes in our minds the quantity of fire, which any subject, at any time, is impregnated with. If different bodies are brought together, though each possesses a different degree of heat, it teaches us to discover what degree of heat they will arrive at when thoroughly mixed, supposing effervescence to produce no alteration in the mixture.

The inventor of this admirable instrument is not certainly known, though the merit of the discovery has been ascribed to several great men, of different nations, in order to do them and their countries honor. It came to us from Italy, about the beginning of the sixteenth century. The first inventors were far from bringing this instrument to its present degree of perfection. As it was not then hermetically sealed, the contained fluid was, at the same time, influenced by the weight of the air, and by the expansion of heat. The academy of Florence added this improvement to their thermometers, which soon made them more generally received; but, as the highest degree of heat of the instrument, constructed by the Florentine gentlemen, was fixed by the action of the strongest rays of the sun in their country, this vague determination, varying in almost every place, and the want of a fixed universal scale, rendered all the observations made with such thermometers of little use to us.

Boyle, Halley, Newton, and several other great men, thought this instrument highly worthy of their attention. They endeavoured to fix two invariable points to reckon from, and, by means of these, to establish a proper division. Monsieur des Amontons is said to have first made use of the degree of boiling water, for graduating his mercurial thermometers. Fahrenheit, indeed, found the pressure of the air, in its greatest latitude, would cause a variation of six degrees in that point; he therefore concluded, a thermometer made at the time when the air is in its middle state, might be sufficiently exact for almost every purpose. Long before the heat of boiling water was settled as a permanent degree, many means were proposed to determine another. The degree of temperature in a deep cave or cellar, where no external air could reach, was imagined by many a proper one; but what that degree truly was, and whether it was fixed and universal, was found too difficult to be determined. At last the freezing point of water was thought of, and though some doubts arose, with Dr. Halley and others, whether water constantly froze at the same degree of cold, Dr. Martine has since, by several experiments, proved this to be beyond all doubt, and this degree is now received for as fixed a point as that of boiling water.

These two degrees being thus determined, the next business was the division of the intermediate space on some scale, that could be generally received. Though there seemed to be no difficulty in this, philosophers of different countries have not been uniform in their determinations, and that which is used in the thermometer at present the most common, and, in other respects, the most perfect, is far from being the simplest.

The liquid wherewith thermometers were to be filled, became the object of another enquiry. Sir Isaac Newton employed, for this purpose, linseed oil; but this, being an unctuous body, is apt to adhere to the sides of the glass, and, when suddenly affected by cold, for want of the parts which thus stick to the sides, does not shew the true degree.

Tinged water was employed by others; but this freezing, when Fahrenheit’s thermometer points 32 degrees, and boiling, when it rises to 212, was, from thence, incapable of denoting any more intense cold or heat.

Spirit of wine, which endures much cold without stagnating, was next made use of; but this liquor, being susceptible of no greater degree of heat than that which, in Fahrenheit’s scale, is expressed by 175, could be of no service where boiling water was concerned.

At last the properest fluid, to answer every purpose, was found to be mercury. This had never been known to freeze[6]; and not to boil under a heat of 600 degrees, and is free from every inconveniency attending other liquors.

As the instrument is entirely founded on this principle, that heat or fire expands all bodies, as cold condenses them, there was a necessity of employing a fluid easy to be dilated. A quantity of it is seated in one part in the bulb. This being expanded by heat, is pushed forward into a fine tube, or capillary cylinder, so small, that the motion of the fluid in it is speedy and perceptible. Some thermometers have been constructed with their reservoir composed of a larger cylinder; but in general, at present, they are made globular. The smaller the bulb is, the sooner it is heated through, and the finer the tube, the greater will be the length of it, and the more distinct the degrees. It is scarcely possible that any glass cylinder, so very small, should be perfectly regular; the quicksilver, during the expansion, passing through some parts of the tube wider than others, the degrees will be shorter in the first case, and longer in the latter. If the divisions, therefore, are made equal between the boiling and freezing points, a thermometer, whose cylinder is irregular, cannot be true. To rectify this inconveniency, the ingenious Mr. Bird, of London, puts into the tube about the length of an inch of mercury; and measuring, with a pair of compasses, the true extent of this body of quicksilver in one place, he moves it from one end to the other, carefully observing where it increases or diminishes in length, thereby ascertaining the parts, and how much the degrees are to be varied. By this contrivance, his thermometers are perfectly accurate, and exceed all that were ever made before.

I shall not trouble my reader with numerous calculations that have been made, to express the quantity of particles of the liquor contained in the bulb, in order to determine how much it is dilated. This, Dr. Martine seems to think a more curious than useful enquiry. It is sufficient, for our purpose, to know how the best thermometers ought to be constructed: they who have leisure and inclination, may be agreeably entertained by the author last cited.

By observing the rise of the mercury in the thermometer, during any given time, as, for instance, during the time of the day, we ascertain the degree and value of the heat of every part of the day, from whence may be fixed the medium of the whole time, or any part thereof. By repeated experiments, it appears, the medium heat of most days is usually indicated at eight o’clock in the morning, if the instrument is placed in the shade, in a northern situation, and out of the reach of any accidental heat.

Though water is not so readily affected as air by heat and cold, yet, as all bodies long exposed in the same place, become of the same degree of heat with the air itself, no great error can arise from estimating water, in general, to be of the same heat as the air, at eight o’clock in the morning, in the shade.

The thermometer teaches us that the heat of boiling water is equal to 212 degrees, and by calculation we may know what quantity of cold water is necessary to bring it to any degree we choose; so, notwithstanding the instrument cannot be used in large vessels, where the water is heating, yet, by the power of numbers, the heat may be ascertained with the greatest accuracy. The rule is this: multiply 212, the heat of boiling water, by the number of barrels of water thus heated, (suppose 22) and the number of barrels of cold water to be added to the former, (suppose 10,) by the heat of the air at eight o’clock, (suppose 50,) add these two products together, and divide by the sum of the barrels; the quotient shews the degree of heat of the water mixed together.

The calculation may be extended to three or more bodies, provided they be brought to the same denomination. Suppose 32 barrels of water to be used where there is a grist of 20 quarters of malt, if these 20 quarters of malt are of a volume or bulk equal to 11 barrels of water, and the malt, by having lain exposed to the air, is of the same degree of heat with the air, in order to know the heat of the mash, the calculation must be thus continued.

We shall meet hereafter with some incidents, which occasion a difference in the calculations made for the purpose of brewing, but of these particular mention will be made in the practical part.

The thermometer, by shewing the different degrees of heat of each part of the year, informs us, at the same time, how necessary it is the proportions of boiling water to cold should be varied to effect an uniform intent; also that the heat of the extracts of small beer should differ proportionably as the heats of the seasons do: it assists us to fix the quantity of hops necessary to be used at different times; how much yeast is requisite, in each term of the year, to carry on a due fermentation; and what variation is to be made in the length of time that worts ought to boil. Indeed, without this knowledge, beers, though brewed in their due season, cannot be regularly fermented, and whenever they prove good, so often may it be said fortune was on the brewer’s side.

Beers are deposited in cellars, to prevent their being affected by the variations of heat and cold in the external air. By means of the thermometer, may be determined the heat of these cellars, the temper the liquor is kept in, and whether it will sooner or later come forward.

The brewing season, and the reason why such season is fittest for brewing, can only be discovered by this instrument. It points out likewise our chance for success, when necessity obliges us to brew in the summer months.

As all vegetable fermentation is carried on in heats, between two settled points, we are, by this instrument, taught to put our worts together at such a temperature, as they shall neither be evaporated by too great a heat, nor retarded by too much cold.

If curiosity should lead us so far, we might likewise determine, by it, the particular strength of each wort, or of every mash; for if water boils at 212 degrees, oil at 600, and worts be a composition of water, oil and salt; the more the heat of a boiling wort exceeds that of boiling water, the more oils and salts must it contain, or the stronger is the wort.

A given quantity of hops, boiled in a given quantity of water, must have a similar effect, consequently the intrinsic value of this vegetable may, in the same manner, be ascertained.

The more the malts are dried, the more do they alter in color, from a white to a light yellow, next to an amber, farther on to a brown, until the color becomes speckled with black; in which state we frequently see it. If more fire or heat is continued, the grain will at last charr, and become intirely black. By observing the degrees of heat necessary to induce these alterations, we may, by the mere inspection of the malt, know with what degree of fire it has been dried; and fixing upon such which best suits our purpose, direct, with the greatest accuracy, not only the heat of the first mash, but the mean heat the whole brewing should be impressed with to answer our intent, circumstances of the greatest consequence to the right management of the process.

If I had not already said enough to convince the brewer of the utility of this instrument, how curious he ought to be in the choice, and how well acquainted with the use of it, I should add the heat gained by the effervescing of malt, is to be determined by it alone; the quantity of heat lost by mashing, by the water in its passage from the copper to the mash ton, and by the extract coming down into the underback, these can be found by no other method; and, above all, that there is no other means to know with certainty the heat of every extract.

I know very well good beers were sometimes, perhaps often, made before the thermometer was known, and still is, by many who are entirely ignorant of it; but this, if not wholly the effect of chance, cannot be said to be very distant from it. They who carry on this process, unassisted by principles and the use of the thermometer, must admit they are frequently unsuccessful, whereas did they carefully and with knowledge apply this instrument, they certainly would not be disappointed.—It is equally true, the brewing art, for a long space of time, has been governed by an ill-conveyed tradition alone; if lucky combinations have sometimes flattered the best practitioners, faulty drinks have as often made them feel the want of certain and well established rules. It is just as absurd for a brewer to refuse the use of the thermometer, as it would be for an architect to reject the informations of his plummet and rule, and to assert they were unserviceable because the first house, and probably many others, were built without their assistance.

SECTION VII.
OF THE VINE, ITS FRUITS, AND JUICES.

After these short accounts of the principles and instrument necessary to the right understanding of the brewing art, we should now draw near to the particular object of this treatise, but as the most successful method to investigate it, must be first to inspect the great and similar example nature has set before us, our time will not be lost by making this enquiry.

Any fermented liquor, that, in distillation, yields an inflammable spirit miscible with water, may be called wine, whatever vegetable matter it is produced from.—As beer and ales contain a spirit exactly answerable to this definition, brewing may justly be called the art of making wines from corn. Those, indeed, which are the produce of the grape, have a particular claim to the name, either because they are the most ancient and the most universal, or that a great part of their previous preparation is owing to the care of nature itself. By observing the agents she employs, and the circumstances under which she acts, we shall find ourselves enabled to follow her steps, and to imitate her operations.

Most grapes contain juices, which, when fermented, become in time as light and pellucid as water, and are possessed of fine spiritous parts, sufficient to cherish, comfort, and even inebriate. But these properties of vinosity are observed not to be equally perfect in the fruits of all vines; some of them are found less, others not at all proper for this purpose. It is therefore necessary to examine the circumstances which attend the forming and ripening of those grapes, whose juices produce the finest liquors of the kind.

All grapes, when they first bud forth, are austere and sour, therefore of a middle nature. And this can be no other than the effect of the autumnal remaining sap, mixed with the new raised vernal one, the consequence of which mixture will be found greatly to merit our inquiry. As far as our senses can judge, at first, it appears that the juice, in this state, consists of somewhat more than an acid combined with a tasteless water. When the fruit is ripe, it becomes full of a rich, sweet, and highly flavoured juice. The color, consistency, and taste of which shew, that, by the power of heat, a considerable quantity of oil has been raised, and, sheathing the salts, is the reason of its saccharine taste and saccharine properties.

In England, grapes are probably produced under the least heat they can be raised by. They discover themselves in their first shape, about June, when the medium heat of the twenty-four hour’s shade is 57,60. This, with what more should be added for the effect of the sun’s beams, are the degrees of heat which first introduce the juices into this fruit.

The highest degrees of heat, in the countries where grapes come to perfect maturity, have been observed to be, in various parts of Italy, Spain, and Greece 100, and at Montpelier 88, in the shade; to which, according to Dr. Lining’s observations, 20 degrees must be added for the effect of the sun’s beams. The greatest heat in Italy will then amount to 120 degrees, and in the south of France to 108. These approach nearly to the strongest heats observed in the hottest climates, which, in Astracan, Syria, Senegal, and Carolina, were from 124 to 126 degrees.

Those countries, where the heat is greatest, in general produce the richest fruits, that is, the most impregnated with sweet, thick and oily juices. We are told, among the Tockay wine-hills, there is one which, directly fronting the south, and being the most exposed to the sun, yields the sweetest and richest grapes. It is called the sugar-hill, and the delicious wines extracted from this particular spot, are all deposited in the cellars of the imperial family. Those grapes, some in the Canaries, some in other places, being suffered to remain the longest on the tree, with their stems half cut through, by this means procure their juices to be highly concentrated, and produce that species of sweet, oily, balmy wines, which, from this operation, are called sack, a derivation of the French word sec or dry.

In all distillations of unfermented vegetables, water and acid salts rise first. A more considerable degree of fire is required for the elevation of oils, and a still greater one for the lixivial salts, which render those oils miscible with water.

A plant, exposed to a very gentle heat, at first yields a water which contains the perfect smell of the vegetable blended with a subtile oil; if more heat be added, an heavier oil will come over: from some a volatile alkali, from others a phlegm will rise, which gradually grows acid; and, last of all, with the farther assistance of fire, the black, thick, empyreumatic sulphur. Nature, in a less degree, may be said to place a like series of events before our eyes, in the forming and maturating of grapes, and it is by imitating what she does, that the inhabitants of different countries may improve the advantages of their soil and of their air.

In order to illustrate the doctrine, that grapes are endued with various properties, in proportion to the heat of the air they have been exposed to, let us remember what Boerhaave has observed, that, in very hot weather, the oleous corpuscles of the earth are carried up into the air, and, descending again, cause the showers and dews in summer to be very different from the pure snow of winter. The first are acrid, and disposed to froth, the last is transparent and insipid. Hence summer rain, or rain falling in hot seasons, is always fruitful, whereas in cold weather it is scarcely so at all. In winter the air abounds with acid parts, neither smoothed by oils nor rarified by heat: cold is the condensing power, as heat is the opener of nature. In summer, the air, dilating itself, penetrates every where, and gives to the rain a disposition to froth, occasioned by the admixture of oleous and aërial particles. Thus the acid salts, either previously existing, or by the vernal heat introduced into the grapes, and necessary to their preservation, are neutralized by coming in contact with the juices the foregoing autumn produced; after which a hotter sun, covering or blending these juices with oils, changes the whole into a saccharine form. In proportion as these acids are more or less sharp, and counterbalanced by a greater or lesser quantity of oils, the juices of grapes approach more or less to the state of perfection, which fermentation requires.

There are many places, as Jamaica, Barbadoes, &c. in which experience shews the vine cannot be cultivated to advantage. By comparing the heat of these places with those in Italy and Montpelier, it appears this defect is not owing to excessive heats, but to their constancy and uniformity; the temperature of the air of these countries seldom being so low as the degree necessary for the first production of the fruit. Whenever the cultivation of the vine is attempted in these parts of the West Indies, the grapes, on their first appearance, are shaded and skreened from the beams of the sun, which, in their infancy, they are not able to bear.

Hence we learn, though nature employs both the autumnal and vernal seasons, yet there are lesser heats with which she prepares the first juice of grapes, a stronger power of the sun she requires to form the fruit, and a greater than either to ripen it. We have investigated the lowest degrees of heat, in which grapes are produced, and nearly the highest they ever receive to ripen them. Let us call the first the germinating degrees, and the last those of maturation. If nearly 58 be the lowest of the one, and 126 the highest of the other, and if a certain power of acids is necessary for the germination of the grapes, which must be counterbalanced by an equal power of oils raised by the heat of the sun for their maturation, then the medium of these two numbers, or 92, maybe said to be a degree at which this fruit cannot possibly be produced, and inferior to that by which it should be maturated. At Panama the lowest degree of heat in the shade is 72, to which 20 being added, for the sun’s beams, the sum will be 92, and consequently no grapes can grow there, except the vines be placed in the shade.

If we recollect that we can scarcely make wine, which will preserve itself, of grapes produced in England, we shall be induced to think, that the reason of this defect is the want of the high degrees of heat. Our sun seldom raises the thermometer to 100 degrees, and that but for a short continuance. Our medium heat is far inferior to 92, and hence we see, at several distant terms in summer, new germinated grapes, but seldom any perfectly ripe. These observations, the use of which, in brewing, we will endeavour to apply, likewise point out to us, what part of our plantations are fit to produce this fruit, and to what degree of perfection.

A research made for each constituent part forming grapes, as well as the proportion they bear to one another, at first sight, appears to be an eligible method to discover the nature of wines; but in every vegetable their parts are mixed and interwoven, and every degree of heat, acting on them, finds these so blended, as to render their division too imperfect for such enquiry to be made with sufficient accuracy, to deduce therefrom the rules of an art. In the producing, ripening, and fermenting the juice of the grapes, as well as in forming beers and ales, the element of fire so superlatively influences and governs every progressive act, as to occasion some remarkable difference in their appearance: from, hence, then, we may expect the information we want, and be enabled to discover the laws by which Nature forms her wines.

When the constituent parts of a subject are to be estimated by heat alone, the number of degrees comprehended between the first heat which formed it, and the last which brought it to a perfect state, must express the whole of its constituent parts. Complete finished substances, must have been benefited by the whole latitude of degrees applicable thereto; and in proportion as part of the whole latitude is wanting, will their nature be different, and themselves less perfect.

This variety is remarkable in the fruit we are now treating of. A country endued with the lowest germinating, and with the highest maturating degrees of heat for grapes, would produce them in the utmost perfection; that is, they would possess all the several properties they could obtain from this circumstance; consequently such are capable of forming wines that would preserve themselves a very long time, and would also become spontaneously fine. From the several heats we have observed that this fruit is capable of enduring, it is reasonable to believe the greatest number of degrees of heat employed to form all their constituent parts, must be where, during the whole space of vegetation, the heat in the shade varies from 60 to 106 degrees, and constitutes a difference of 46 degrees. So great a latitude, ordered by nature, most certainly denotes the general utility of the plant.

The climate of the southern part of France approaches nearest to this; but Spanish wines are richer; their grapes are formed by a warmer sun; their vernal and maturating heats exceed those of France; but, at the same time, their wines are more stubborn, and, to be made fine, require the help of precipitation. This variety increases according to the heat of climates: thus we see wines which come from the coast of Africa, whose richness and stubbornness are beyond the reach of any menstruum employed to fine them. Let us endeavour to reduce this apparent inconstancy to rule, in order to assist our art.—If the lowest heat which forms the grape, in the southern parts of France, be 60 degrees, and if 88 degrees, in the shade, be the mean of their maturating heat, the difference between 60 and 88, or 28 degrees, is the number which includes the constituent parts of grapes in this country, as these degrees imply the whole space of their progress. If like juices were to be imitated by art, as in our hot-houses, it is clear half the number of the degrees of heat which form the whole of the constituent parts, or 14, deducted from 74, the mean heat of their whole vegetation, would give 60, for the first heat to be employed, and this to be raised, for maturation, to 88, the greatest heat, nature in this case, permits, or 14 degrees to be added to the same whole mean. To liken the wines of Spain, where the autumnal and vernal heats are greater than in France, the heat forming the first juices must be more, as also the maturating heats; but with such practice, the number of constituent degrees would be found to be fewer, and spontaneous brightness could no more be expected, than it is found, in their wines.

A strict enquiry after the heats first and last applied to grapes, is of such consequence to ascertain the principles by which malt liquor should be formed, that, though grapes produced in England scarcely make wines which can maintain themselves sound, yet, as the rule is universal, even from them we shall be able to establish not only its certainty, but also the application of the number of the degrees found between the heats which germinate the fruit, and those which ripen them.

If, from their medium, 59.35, we subtract 1.75, half their difference, or half their constituent parts, we must have left 57.60 for the germinating heat; and if to their medium, 59.35, we add 1.75, half the number of their constituent parts, we shall have 61.10, the highest mean heat, in the shade, at the time the richest juices of our grapes are formed. It is true, in July, nor even in the following months, when the heat continues nearly alike, our grapes are not ripe, nor gathered; the properties raised by our greatest sunshine, as yet have not reached the fruit, and though the mean heat of the air in September and October is less, yet it is sufficient to place in the grapes the juices raised by the preceding hot sun, which concentrate and grow richer, by remaining on the plant, though, for want of a sufficient heat, they do not reach that perfection obtained in warmer climates.

The want of grapes in many parts both of America and Africa, and the reason we gave for this, (See page 55,) warrants the truth of the division we have just now made, between the germinating and maturating heats; and if the effects caused by a hot sun do not immediately benefit the fruit, by a parity of reason, after the grapes are gathered, the plant must possess, (and surely for some longer space, by a continued heat, equal, and often superior, to the vernal sun,) juices which Nature is too frugal not usefully to apply; these juices, we apprehend, assist in forming the embryo of the leaves which are fully to expand the ensuing year, and serve, by their oleaginous quality, to preserve these and the whole plant during the cold of the winter; which cold, at the same time that it contracts the pores of the vine, condenses and thickens these richer juices, from whence few, if any of them, are lost or expended by perspiration. The heat of the following spring renews their activity, when blending with those this season attracts, the leaves open, the flowers appear, and the fruit forms. Thus far we conceive the act of germination extends, provided for and assisted both by the autumnal and vernal heats, and which, in point of power, are nearly equal and uniform.

The heat of the sun, during summer months, and if to this we add the more constant heat at the roots of the vine, retained there by the density of the earth; these (though superior to the germinating heat) produce a like uniformity for maturating the fruit: thus nature, in order to implant in wines an original even taste, and to facilitate the fermentable act, amidst the great variety that appears to us in the heat of the air, seems, upon the whole, to act by steady and equal motions; or rather, perhaps, this is the best manner by which we can reduce to rule; the inconstancy of the atmosphere.

I am sensible these facts had been represented in a more natural light, had I observed the degrees of heat impressed on the vine in every season of the year; the difference of the sun’s heat, in every hour of the day, a variety exceeding that in the shade; that between night and day; the aspect of the plant; the heat of the earth at its surface, as well as at the roots of the vine; all these would have increased the circumstances to a prodigious extent; which, though perhaps requisite to satisfy philosophic investigation, might, from their number and variety, have been the means rather to induce us to error, than to discover the general rules by which nature acts.

From the above-related process we are taught, that nature, in forming wines, is not confined to a certain fixed number of degrees, but admits, for this act, of a considerable latitude, according to the extent of which the wines vary in taste and properties; and that she affects an equality of heat in each period of vegetation; from whence the brewer is taught, if he form his malt-liquors with four mashes, as in the autumn and spring the vine is impressed with heats nearly uniform, so ought his two first mashes to be; the third, in imitation of the high heat of summer, should be much hotter, and the heat of his last mash the same with this; and this general rule has been found universally true, for beers expected to preserve themselves sound a sufficient time; and admits but of a proportional variation, when fewer or more mashes are employed, as the degrees of heat denominating the constituent parts of the grain, must be applied in proportion to the quantity of water used to each mash; but in malt liquors speedily to be drank, or when we deviate greatly from the more perfect productions of nature, we are then compelled to swerve from her rules; a practice never profitable, and which nothing but necessity can justify.

The nature of the soil proper for the vine, might, in another work, be a very useful enquiry. It will be sufficient here, barely to hint at the effect, which lixivial soils produce in musts. The Portugueze, when they discovered the Island of Madeira in 1420, set fire to the forests, with which it was totally covered. It continued to burn for the space of seven years, after which the land was found extremely fruitful, and yielding such wines, as, at present, we have from thence, though in greater plenty. It is very difficult to fine these wines, and, though the climate of this island is more temperate than that of the Canaries, the wines are obliged to be carried to the Indies and the warmer parts of the globe, to be purged, shook, and attenuated, before they can arrive to an equal degree of fineness with other wines; were the Portugueze acquainted with what may be termed the artificial method of exciting periodical fermentation, much or the whole of this trouble might be avoided. Hence we see, that soils impregnated with alkaline salts will produce musts able to support themselves longer, and to resist acidity more, than other soils, under the same degree of heat.

Grapes have the same constituent parts as other vegetables. The difference between them, as to their tastes and properties, consists in the parts being mixed in different proportions. This arises, either from their absorbent vessels more readily attracting some juices than others, or from their preparing them otherwise, under different heats and in different soils.

We find, says Dr. Hales, by the chymical analysis of vegetables, that their substance is composed of sulphur, volatile salts, water, and earth, which principles are endued with mutual attracting powers. There enters likewise in the composition, a large portion of air, which has a wonderful property of attracting in a fixed, or of repelling in an elastic state, with a power superior to vast compressing forces. It is by the infinite combinations, actions, and reactions of these principles, that all the operations in animal and vegetable bodies are effected.—Boerhaave, who is somewhat more particular with regard to the constituent parts of vegetables, says, that they contain an oil mixed with a salt in form of a sapo, and that a saponaceous juice arises from the mixture of water with the former.

Thus we see, from the composition of grapes, that they have all the necessary principles to form a most exquisite liquor, capable, by a gentle heat, to be greatly attenuated. They abound with elastic air, water, oils, acid, and neutral salts, and even saponaceous juices.—The air contained in the interstices of fluids is more in quantity than is commonly apprehended. Sir Isaac Newton has proved that water has forty times more pores than solid parts; and the proportion, likely, is not very different in vegetable juices. When the fruit is in its natural entire state, the viscidity of the juices, and their being enveloped by an outward skin, prevent the expansion of the inclosed air; it lies as it were inactive. In this forced state, it causes no visible motion, nor are the principles, thus confined, either subjected to any apparent impressions of the external atmosphere, or so intimately blended as when they are expressed. A free communication of the external air, with that contained in the interstices of the liquor, is required to form a perfect mixture. By what means this is effected, what alterations it produces, or, in general, in what manner the juice of the grape becomes wines, must be the subject of our next inquiry.

The process of a perfect fermentation is undoubtedly the same (where the due proportions of the constituent parts, forming the must, are exactly kept) whatever vegetable juices it is excited in. For this reason, we will observe the progress of this act in beers and ales, these being subjects we are more accustomed to, and where the characters appear more distinct, in order to apply what may be learned from thence to our chief object, the business of the brewer.

SECTION VIII.
OF FERMENTATION IN GENERAL.

Vegetable fermentation is that act, by which oils and earth, naturally tenacious, by the interposition of salts and heats, are so much attenuated and divided, as to be made miscible with, and to be suspended in, an homogeneous pellucid fluid; which, by a due proportion of the different principles, is preserved from precipitation and evaporation. According to Boerhaave, a less heat than forty degrees leaves the mass in an inert state, and the particles fall to the bottom in proportion to their gravity; a greater heat than eighty degrees disperses them too much, and leaves the residuum a rancid, acrimonious, putrid mass.

It is certainly very difficult, if not impossible, to discover the true and adequate cause of fermentation. But, by tracing its several stages, circumstances, and effects, we may perhaps perceive the agents and means employed by nature to produce this singular change; a degree of knowledge, which, we hope, is sufficient to answer our practical purposes.

The must, when just pressed from the grapes, is a liquid, composed of neutral and lixivial salts, oils of different spissitude, water, earth, and elastic air. These, irregularly ranged, if I may be permitted the expression, compose a chaos of wine. Soon after the liquor is settled, a number of air bubbles arise, and at first adhere to the sides of the containing vessel; their magnitude increases as they augment in number, so that at last they cover the whole surface of the must.

It has been long suspected, and, if I mistake not, demonstrated, that an acid, of which all others are but so many different species, is universally dispersed through, and continually circulating in, the air; and that this is one of nature’s principal agents, in maturating and resolving of bodies. Musts, like other bodies, being porous, the circulating acids very powerfully introduce themselves therein by the pressure of the atmosphere, in proportion as the pores are more or less expanded by the heat they are exposed to. The particles of acids are supposed by Newton to be endued with a great attractive force, in which their activity consists. By this force, they rush towards other bodies, put the fluid in motion, excite heat, and violently separate some particles in such manner as to generate or expel air, and consequently bubbles.

From hence it appears that, as soon as the acid particles of the air are admitted into the must, they act on the oils, and excite a motion somewhat like the effervescence generated, when acids and oils come in contact, though in a less degree. This motion is the cause of heat, by which the included elastic air, being rarefied, occasions the bubbles to ascend towards the surface.—These, by the power of attraction, are drawn to the sides of the vessel; at first they are small and few, but increase, both in number and magnitude, as the effect of the air continues, till, at last, they spread over the whole surface. The first stage of vegetable fermentation shews itself to be a motion excited by the acids floating in the air, acting on the oleous parts of the liquor, which motion gives an opportunity to the divided minute parts of air, dispersed throughout the whole, to collect themselves in masses: from hence they become capable to exert their elasticity, and to free themselves from the must. (See Arbuthnot on air p. 116.) It may, perhaps, be proper to observe, that all musts, which ferment spontaneously, contain for this purpose a large portion of elastic air.

Bubbles still continue to rise after the must is entirely covered with them; and a body of bladders is formed, called, by the brewers, the head of the drink; as the bubbles increase, the head rises in height, but the oils of the must, being as yet of different spissitudes, those which are least tenacious soon emit their air; others, somewhat stronger, being rarefied by the fermenting heat, rise on the surface higher than the rest, while such aerial bubbles as are more dense, take their place below them. From hence, and from the constituent parts of the drink not being as yet intimately mixed, the head takes an uneven and irregular shape, and appears like a beautiful piece of rock work. After this, it requires some time, and it is by degrees, that the particles dispose themselves in their due order, to be farther attenuated by the act of fermentation, which, when effected, the saline, oily, and spiritous parts become perfectly miscible with the water. The head of the liquor then is more level; heterogeneous bodies, as dirt, straw, corks, &c. assisted by bubbles of air adhering to them, are now buoyed on the surface, and should be skimmed off, lest, when the liquor becomes more light and spiritous, they should subside. About this time, such parts of the must as are too course to be absorbed in the wine (as they consist chiefly of pinguious oils, mixed with earth, though they strongly envelope much elastic air) from their weight, sink to the bottom, and form the lees. But the internal motion increasing, the air bubbles grow larger; some, not formed of parts so strong as the others, which generally are the first, burst and strengthen the rest; and thereby a heat is retained in the fermenting liquor, which carries the act on to a farther degree. The particles of the must become more pungent and spiritous, because more fine and more active; some of the most volatile ones fly off; hence, that subtle and dangerous vapor, called gas, which extinguishes flame and suffocates animals. The wine, by these repeated acts, being greatly attenuated, is at last unable to support, on its surface, the weight of such a quantity of froth, rendered more dense by the repeated explosions of the air bubbles. Now, lest the liquor should be fouled by the falling in of the froth, it is put in vessels having only a small aperture, where it continues to ferment, with a slower and less perceptible motion, which gradually diminishing until it reaches the period when it neither attracts or repels air, it admits of its communication with it to be cut off; not that thereby, in a strict sense, the fermentation can be said to be completely ended: the least heat is sufficient to renew, or rather to continue the act, more especially if by any means the atmosphere can gain any admittance, however small.

The alteration caused in the liquor, by the pressure of the external air, from the very first of its fermenting, not only occasions the particles of the must to form themselves in their due order, but also, by the weight and action of that element, grinds and reduces them into smaller parts. From hence they more intimately blend with each other, the wine becomes of an equal and even taste, and if the constituent parts of the must be in a perfect proportion, it will continue to ferment, until, these being disposed and ranged in right lines, a fine and pellucid fluid is produced.

That this operation subsists, even after the liquor becomes fine, is evident; for every fretting is a continuance of fermentation, though often almost imperceptible. Thus, the component parts of the liquor are continually reduced to a less volume, the oils become more attenuated, and less capable of retaining elastic air. As these frettings are often repeated, it is impossible to determine, by any rule, the exact state in which wine should be, in order to be perfect for use. It would seem, however, that the more minutely the parts are reduced, the more their pungency will appear, and the easier their passage be in the human frame. Both wines and beers, when new, possess more elastic air, than when meliorated by age; to be wholesome, they must be possessed of the whole of the fermentable principles. For these reasons, beers and ales, when substituted for wines in common, and more especially when given to the sick, should always be brewed from entire malt: for the last extracts, possessing but the inferior virtues of the grain, have by so much less the power to become light, spiritous, and transparent.

Wines never totally remain inactive; fermentation in some degree continues, and in time the oils, by being greatly attenuated, volatilise, fly off, and permit a readier admission of the external air into the drink. In proportion as this circumstance takes place, the latent acids of the liquor shew themselves, the wine becomes sour, and in this state is termed vinegar.

Its last stage or termination is, when the remaining active principles, which the vinegar possessed, being evaporated in the air, a pellicle forms itself on the surface of the liquor, and dust and seeds, which always float in the atmosphere, depositing themselves thereon, strengthen this film into a crust, on which grows moss, and many other small plants. These vegetables, together with the air, exhaust the watery parts; after which no signs of fermentable principles remain but, like the rest of created beings, all their virtues being lost, what is left is a substance resembling common earth.

Upon the whole, then, it appears, that a liquor fit for fermentation must be composed of water, acids smoothed over with oils, or saccharine salts, and a certain portion of elastic air; the heat of the air the liquor is fermented in, must be in proportion to the density of its oils; and lastly, that the pores are to be expanded by slow degrees, lest the air, by being admitted too hastily, should cause an effervescence rather than a fermentation, and occasion the whole to become sour. Wines, therefore, fermented in countries where the autumn is hot, require their oils to be more pinguious, than where the season is cooler. For the same reason beers are best made, when the air is at forty degrees of heat, or below the first fermentable point, because the brewer, in this case, can put his wort to work, at a heat of his own chusing, which will not be increased by that of the air; on the contrary, when, by its internal motion, the heat becomes greater, it will again be abated and regulated by the cold of the medium.

The pores of a wort are expanded in proportion to the heat it is impressed with; on which account common small beer, brewed in summer, when the air and acids more easily insinuate themselves into the liquor, ought to be enriched with oils obtained by hotter extracts, to sheath these salts; and in winter the contrary method must be pursued.

From this history of fermentation, we can, with propriety, account for the many accidents and varieties that accompany this act; and a comparative review of some of them may not be unnecessary.

A cold air, closing the pores of the liquor, always retards, and sometimes stops, fermentation; heat, on the contrary, constantly forwards this act; but, if carried too high, immediately prevents it.

A must, loaded with oils, will ferment with more difficulty than one which abounds with acids; it likewise is longer before it becomes perfectly fine; but, when once so, will be more lasting.

If the quantities of oil are increased, they will exceed the power both of the acids naturally contained in the must, and of those absorbed from the air in fermenting; the liquor will therefore require a longer time before it becomes pellucid, unless assisted by precipitation: and there may be cases where even precipitation cannot fine it.

These considerations naturally lead us to a general division of wines into three classes: First, of such as soon grow fine, and soon become acid, being the growth of cold countries. Secondly, of those which, by a due proportion of heat, both when the grapes germinate, and when they come to maturity, form a perfect must; and not only preserve themselves, but, in due time, (more especially when assisted by precipitation,) become transparent; and, thirdly, of such as, having taken their first form under the highest degrees of germination, (as I termed them) are replete with oils, disappoint the cooper, and render the application of menstruums useless, unless in such quantities as to change the very nature of the wine.

This remarkable difference in wines appears chiefly to arise from the climate; and it will confirm the observation before made, that, as wines are neither naturally nor uniformly perfect, they must be subject to many diseases.

All vegetable substances possess fermentable principles, though in a diversity of proportions; for those juices only, whose constituent parts approach to the proportion necessary for the act of fermentation, can be made into wines. I would not, however, from what I have attributed to a difference of heat in different climates, be understood, as if I thought that vegetables are more or less acid, more or less sulphureous, or in general more or less fermentable, merely from the heat of the country they grow in. This, though likely one of the principal causes of their being so, is by no means the only one; the form and constitution of the plant is another. In very hot climates, we find acid fruits, such as limes, tamarinds, lemons, and oranges; the proportions of fermentable principles in these fruits are such, as to render them incapable of making sound wines, though their juices may, in some degree, be susceptible of fermentation. In countries greatly favored by the sun, some vines and other fruit trees there are, which attract the acids from the air, and possibly from the earth, so greedily, that, when their juices are fermented, they soon become sour. On the contrary, in cold climates, we see warm aromatic vegetables grow, as hops, horse-raddish, camomile, wormwood, &c. whose principles cannot, without difficulty, and perhaps not perceptibly, be brought to ferment. But these instances must be accounted the extremes on each sides; for in cold, as well as in hot countries, fruits are produced susceptible of a perfect natural fermentation: with us, for example, apples; some species of which are endued with such austere and aromatic qualities, that their expressed juices ferment spontaneously, until they become pellucid, and are capable of remaining in a sound state many years. From hence it appears, that proper subjects, which will naturally ferment, for making wines, may be found in almost every climate. England, says Boerhaave, on this account, is remarkably happy: her fruits are capable of producing a great variety of wines, equal in goodness to many imported, were not our tastes but too often subservient, not to reason, but to custom and prejudice.

A similar want of perfection to that observed in wines, may be noticed in our beers and ales, and it chiefly has its origin in the different degrees of heat the malt has been impressed with, both in drying and extracting; where, in the processes of malting and brewing, a sufficient heat has not been maintained, the liquor undoubtedly must become acid; in proportion as the contrary is the case, or that the beer is overcharged with hops, if this is in no great excess, it retains still a greater tendency to fermentation than to putrefaction, acids not being wanting, but only enveloped. In this case, time will get the better of the disease; like to the wines made from the growth of too hot a sun, these liquors, at a certain period, sicken, smell rancid, and have a disagreeable taste, but, by long standing, they begin to fret, and, receiving more acids from the air, recover their former health, and improve in taste.

But should the quantity of oils exceed this last proportion, in wines formed from corn, the must, instead of fermenting, would putrify, even though, by some means, elastic air has been driven into them. In this case, the over proportion of the oil, and its tenacity, prevents the entrance of the acids, the wort receives no enlivening principle from without, and the air, at first conveyed into it, is enveloped with oils so tenacious as to be incapable of action. Nothing so much accelerates putrefaction as heat, moisture, and a stagnating air; and all substances corrupt, sooner or later, in proportion to the inactivity of the contained air, to the want of a proper vent, and to the closeness of their confinement. Besides these cases, beers and ales, as well as wines, sometimes are vapid and flat, without being sour; this does not so much arise from the imbibing the air of the atmosphere, as from their fermenting, generating and casting off too much air of their own. To prevent this accident, they are best preserved in cool cellars, where their active invigorating principles are kept within due bounds, and not suffered to fly off. These facts ought to convince us of the truth, deduced by Dr. Hales, from many experiments, that there is a great plenty of air incorporated in the substance of vegetables, which, by the action of fermentation, is roused into an elastic state, and is as instrumental to produce this act, as it is necessary to the life and being of animals.

I should here close this short and imperfect account; but as, in the art of brewing, there is no part so difficult, and at the same time so important to be in some measure understood, as the cause and effects of fermentation; and as the examination of this act, in all the different lights in which it offers itself to our notice, can hardly be thought uninteresting, these few detached thoughts I hope will be allowed of.

The effect of the act of fermentation on liquors is, so to attenuate the oils; as to cause them to become spiritous, and easily inflammable. When a wine is dispossessed of such oils, which is nearly the case in vinegar, far from possessing a heating or inebriating quality, it refreshes and becomes a remedy against intoxication. The term of fermentation ought, perhaps, only to be applied to that operation which occasions the expressed juices of vegetables to become wine: but as several acts have assumed the same name, it may not be improper here to notice the difference between them.

Vegetation, one of them, is that operation of nature wherein more air is attracted than repelled. I believe all that has been said above, concerning the juice of grapes, is a convincing proof thereof.

Fermentation is, where the communication of the external and internal air of a must is open, and in a perfect state; when the power of repelling, is equal to that of attracting, air.

Putrefaction is when, by the power of strong oils, or otherwise, the communication between the external and the internal air of the must is cut off, so that the liquor neither attracts the one nor repels the other, but, by an intestine motion, the united particles separate and tend to fly off.

Effervescence is when, by the power of attraction, the particles of matter so hastily rush into contact, as to generate a heat which expels the enclosed air; and this more or less in proportion to the motion excited.

SECTION IX.
OF ARTIFICIAL FERMENTATION.

By what has been said, it appears, that, though fermentation is brought on by uniform causes, and productive of similar effects, it is subject to many varieties, both in respect to its circumstances and to its perfection. One difference is obvious, and seems to deserve our attention, as it furnishes a useful division between natural and artificial fermentation. The first rises spontaneously, and requires nothing to answer all the necessary purposes, but the perfection of the juices, and the advantage of a proper heat. The other, at first sight less perfect, wants the assistance of ferments, or substitutes, without which the act could, either not at all, or very imperfectly, be excited.

There are undoubtedly liquors, which, though they have of themselves a tendency to fermentation, and are naturally brought to it, yet, from some defect in the proportions of their constituent parts, either do not acquire a proper transparency, or cannot maintain themselves in a sound state for a sufficient time. These disadvantages, inbred with them, can hardly ever be entirely removed; they gain very little, especially the latter, from age, and therefore are really inferior to liquors, which require the assistance of substituted ferments, to become real wines. In some artificial fermentations, the ferments are so duly and properly supplied, and so intimately blended with the liquor, that in the end they approach very near to, and even vie with, the most perfect natural wines. Were I to enter into a more minute detail, it might be shewn, that wines, when transported from a hot climate to a cold one, are often hurt and checked in the progress of the repeated frettings they require; from whence they become or remain imperfect, unless racked off from their grosser lees, or precipitated with strong menstruums; whereas beers may be so brewed, as to be adapted either to a hot or a cold region, not only without any disadvantage, but with considerable improvements.

Hitherto I have considered grapes as a most pulpous fruit, sufficient to furnish the quantity of water necessary for extracting its other parts; but the natives of the countries where this fruit abounds, in order to preserve them, as near as possible in their primitive state, after they are gathered, suspend them in barns, or place them in ovens, to dry. Thus, being in great measure divested of their aqueous parts, these grapes remain almost inactive, and without juices sufficient to form wines.

In all bodies, the various proportions of their constituent parts produce different effects; hence they remain more or less in a durable state, and tend either to inaction, fermentation, or putrefaction. Now, by a judicious substitution of such parts as shall be wanting, they are nearly, if not wholly, restored to their pristine nature, as may be proved by the observations and experiments communicated to the public by Dr. Pringle. Thus grapes, though dried and exported from their natural climate to another, by the addition of water only, ferment spontaneously, and form wines very near alike to such as they would have produced before. It may, with confidence, be said, that, when any considerable difference appears, it arises from the injudicious manner in which the water is administered, from the fruit not being duly macerated, or from want of such heat being conveyed to the water and fruit, as the juices would have had, if they had been expressed out of the grapes when just gathered; often from the whimsical mixture of other bodies therewith, and perhaps too from the quantity of brandy, which is always put to wines abroad, to prevent their fretting on board a ship. Upon the whole, though, from what just now has been observed, some small difference must take place, it rather proves than contradicts the fact, that, a due quantity of water being applied to dry raisins, an extract may be formed, which will be impregnated with all the necessary constituent parts the grapes had in them when ripe upon the vine, consequently will spontaneously ferment, and make a vinous liquor. Water then, in this case, becomes a substitute, and the liquors produced in this manner may be accounted of the first class of artificial wines.

Vegetables, in their original state, are divisible into the pulpous and farinaceous kinds, both possessing the same constituent parts, though in different proportions. If from the farinaceous such parts be taken away as they superabound in, and others be added, of which they are defective, these vegetables may, by such means, be brought to resemble, in the proportion of their parts, more especially in their musts, the natural wines I have before been treating of: and these being universally acknowledged to be the standard of wines, the nearer any fermented liquor approaches thereto, by its lightness, transparency, and taste, the greater must its perfection be.

To enquire which of the pulpous or which of the farinaceous kinds of vegetables are fittest for the purpose of wine-making, would here be an unnecessary digression. Experience, the best guide, hath, on the one side, given the preference to the fruit of the vine, and on the other to barley. To make a vinous liquor from barley, having all the properties of that produced from the grape, is a task, which can only be compassed by rendering the wort of these, similar to the must of the other.

As malt liquors require the addition of other substitutes, besides water, to, become perfect wines, they can only be ranked in the second class of artificial fermentation. These substitutes are properly called ferments, and merit the brewer’s closest attention.

Ferments, in general, such as yeast, flowers or lees of wine, honey, the expressed juices of ripe fruits, are subjects more or less replete with elastic air, and convey the same to musts, which stand in need thereof. Boerhaave has ranged these, and several others, in different classes, according to their different powers, or rather in proportion to the quantity of air they contain for this purpose.

The juice of the grape, when fermented, forms more lees than the extracts of malt. May we not, from thence, infer that, in the fruit, the elastic air is both more abundant, and contained in a greater number of stronger, though smaller, vesicles, than it is in the malt? The barley, being first saturated with water, germinated only, and then dried with a heat far exceeding that which ripened it, or that which fermentation admits of, has its air in part driven out. The expulsion of air from the worts of beers and ales is still farther effected by the long boiling they undergo. Hence the necessity of replacing the lost elastic air, in order that these extracts may become fermentable. This is effected by means of the yeast, which, consisting of a collection of small bubbles, filled with air, and ready to burst by a sufficient heat, becomes the ferment, which facilitates the change of the wort into a vinous liquor.

The musts of malt generally produce two gallons of yeast from eight bushels of the grain, whereas, in the coldest fermentable weather, and for the speediest purpose, one gallon of yeast is sufficient to work this quantity of malt. Much elastic air still remains in beer, or wine from corn, after the first part of the fermentation is over; for the liquor, separated from the yeast above mentioned, is, at the time of this separation, neither flat, vapid, nor sour; but as yeast, the lees and flowers of malt liquors are of a weaker texture than those of grapes, all artificial fermentations should be carried on in the coolest and slowest manner possible: and beers, but more especially such as are brewed from high-dried, brown malts, (the heat of whose extracts approaches much nearer to that which dried the grain, than is the case in brewing pale malt) ought not to be racked from their lees, as it is frequently practised for natural wines, unless, on account of some defect, they are to be blended with fresh worts under a new fermentation.

As all ferments are liable to be tainted, great care ought to be taken in the choice of them, every imperfection in the ferment being readily communicated to the must. It would not, therefore, be an improper question to be determined by physicians, whether, in a time of sickness, the use of those which have been made in infected places ought to be permitted, and whether, at all times, a drink fermented in a pure and wholesome air is not preferable to that which is made among fogs, smoke, and nauseous stenches.[7]

Wines from corn are distinguished by two appellations, viz., those of ale and beer. As each of these liquors have suffered in character, either from prejudice or want of a sufficient enquiry, it may be proper to levy the objections made against their use, before we enquire into the means of forming them. The most certain sign of the wholesomeness of wines is transparency and lightness; yet some, which are rich, more especially ales, though perfectly fine, have been said to be viscid.—Transparency appears indeed in many wines, before the oils are attenuated to their highest perfection, and some viscidity may therefore be consistent with some degree of brightness. Where the power of the oils and the salts are equal, which is denoted by the transparency of the liquor, viscidity can only arise from the want of age: this cannot be said to be a defect in, but only misapplication of the liquor, by being used too soon.

That beers retain igneous or fiery particles, seems equally a mistake. Malt dried to keep, has undoubtedly its particles removed by fire, so far as the cohesion of them is thereby destroyed, otherwise it would not be in a fit state to preserve itself sound, or readily to be extracted. For this reason, when the grain comes in contact with the water, which is to resolve it, an effervescent heat is generated, which adds to the extracting power, and should be looked on by the brewer as an auxiliary help; but it is impossible that the malt, or the must, should ever inclose and confine the whole or part of fire employed to form them. Fire is of so subtile a nature, that its particles, when contained in a body, continually tend to fly off, and mix with the surrounding air; so that only an equal degree, with what is in the atmosphere, can be continued in the grain, or any liquor whatever, after it has been, for some time, exposed thereto.—Brown beers, made from malt more dried than any other, from experience, are found to be less heating than liquors brewed from pale malt; which probably arises from hence, that brown beers contain a less quantity of elastic air than pale beers, as pale malt liquors contain less than wines, produced from vegetables in their natural state: and as malt liquors contain their elastic air in bubbles of a weaker consistence than those made from the juices of the grape, the effect of beer, when taken in an over-abundant quantity, is neither of so long a continuance, nor so powerful as that of wine, supposing the quality and quantity of each to be equal. This may appear to some persons to be the effect of prejudice, yet it is but a justice due to the produce of my country, to add, that some physicians have given it as their opinion, that strong drinks from malt are less pernicious than those produced from grapes. As far as these gentlemen have, I hope I may advance, without being thought guilty of assuming too much, or countenancing debauch, by pointing out the wines that occasion the fewest disorders.

SECTION X.
OF THE NATURE OF BARLEY.

Barley is a spicated, oblong, ventricose seed, pointed at each end, and marked with a longitudinal furrow. The essential constitution of the parts, in all plants, says Dr. Grew, is the same: thus this seed, like those which have lobes, is furnished with radical vessels, which, having a correspondence with the whole body of the corn, are always ready, when moistened, to administer support to the plume of the embryo, usually called the acrospire. These radical vessels, at first, receive their nourishment from a great number of glandules dispersed almost every where in the grain, whose pulpous parts strain and refine this food, so as to fit it to enter the capillary tubes; and such an abundant provision is made for the nourishment of the infant plant, that the same author says, these glandules take up more than nine tenths of the seed.

Barley is sown about March, sooner or later, according to the season or soil that is to receive it, and generally housed from ten to twenty weeks after. Most plants, which so hastily perform the office of vegetation, are remarkable for having their vessels proportionably larger; and that these may be thus formed, the seed must contain a greater quantity of tenacious oils, in proportion to those seeds, whose vessels being smaller, require more time to perform their growth and come to maturity. This grain, as may be observed, grows and ripens with the lower degrees of natural heat; from whence, and from the largeness of the size of its absorbent vessels, it must receive a great portion of acid parts. It is said to be viscid, though, at the same time, a great cooler, water boiled with it being often drunk as such; and, however it be prepared, it never heats the body when unfermented.

From these circumstances, of its being viscous and replete with acids, it would at first appear to be a most unfit vegetable, from which vinous liquors, to be long kept, should be made; and, indeed, the extracts from it, in its original state, are not only clammy, but soon become sour.

When the grain is at full maturity, its constituent parts seem to be differently disposed than when in a state of vegetation. By germination alone all its principles are put in action; the fibrous parts possess themselves of a great quantity of tenacious oils, leaving the glandules and finer vessels replete with water, salts, and the purest sulphur. If, in this state, the corn is placed in such a situation, that, by heat, the acid and watery parts may be evaporated, the more such heat is suffered to affect it, the more dry, and less acid, will the corn become; its parts will be divided—its viscidity removed; its taste becomes saccharine, by the acids being sheathed or covered over with oils; and these last be rendered more tenacious in proportion to the greater quantity of heat they are made to endure. This process, regularly carried on, is termed malting, and will hereafter be explained more at large.

But, before we enter thereon, it is necessary to consider the state of the grain as it comes from the field.—When mowed, though, upon the whole, it may be said to be ripe, yet every individual part, or every corn, cannot be so. In some seasons, this inequality is so remarkable, as to be distinguished by the eye. The difference in the situation, the soil, and the weather, the changes of the winds, the shelter some parts of the field have had from such winds, are sufficient to account for this, and a much greater variety. When the greater part of the corn is supposed to have come to maturity, it is cut and stacked; the ripest parts having the least moisture, and the fewest acids, as the greenest abound in both. In this state the unripe grains of the corn communicate, to such as are more dry, their moisture and acid parts, which, coming in contact with their oils, an agitation ensues, more or less gentle, in proportion to the power of the acids and water; and from hence is generated a heat, the degree whereof is with difficulty determined.

When this sweating in the mow is kept within its proper limits, the whole heap of the corn, after this internal emotion is over, becomes of one equable dryness, and is not discoloured; but if the grain be put together too wet or too green, the effervescence occasioned thereby will produce such a violent intestine heat, as to charr and blacken the greatest part thereof, nay often make it burst into actual flame.

The effect which a moderate and gentle heat has on the corn, is that of driving the oils towards the external parts of its vessels and skin: by this means, it becomes more capable to preserve itself against the injuries of the weather. The more it is in this state, the backwarder will it be to germinate, when used to this purpose; and if this act is carried too far, or to somewhat like what we have just now mentioned, the plume and root of the enclosed embryo must be scorched, the corn become inert, and incapable of vegetation. This effect is produced by a motion sufficient to remove the particles of the grain from each other beyond their sphere of attraction; and the heat, by which this motion is excited, has been found, in malted corn, to be at about 120 degrees.

It is likely, that vegetables, in general, are susceptible of a large latitude in this respect, according to their different textures. The degree of heat just now mentioned may, perhaps, be applicable to barley alone; the seeds of some grapes endure 126 degrees of heat, and may be capable of being impressed with more, and yet vegetate. But, with corn, if their oils have endured so great a heat, as thereby to be discolored, the seed can by no means be revived. The color of the grain properly indicates the healthy state of the embryo, or future plant; but this, more immediately, is the business of the farmer and maltster, than that of the brewer.

Thus, though it may be disadvantageous to the maltster to steep grain which has not sweated in the mow, as, for want of this, it will not equally imbibe the water; so barley, that is over-heated, or mow burnt, cannot be fit for his purpose. It is, in fact, scarcely possible that any large quantity of barley, from the same stack, should make equally perfect malt, as, on its being put together, the heat generated is always greatest in the centre of the rick, and considerably more there than in its exterior parts.

SECTION XI.
OF MALTING.