Project Gutenberg's The Theory and Practice of Brewing, by Michael Combrune This eBook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org. If you are not located in the United States, you'll have to check the laws of the country where you are located before using this ebook. Title: The Theory and Practice of Brewing Author: Michael Combrune Release Date: March 18, 2018 [EBook #56784] Language: English Character set encoding: UTF-8 *** START OF THIS PROJECT GUTENBERG EBOOK THE THEORY AND PRACTICE OF BREWING *** Produced by Chris Curnow, Turgut Dincer and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive) 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. i 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. Page PART I. Explanation of technical terms, 1 SECTION I. Of Fire, 13 SECTION II. Of Air, 19 SECTION III. Of Water, 24 SECTION IV. Of Earth, 33 SECTION. V. Of Menstruums or Dissolvents, 34 SECTION VI. Of the Thermometer, 39 SECTION VII. Of the Vine, its fruits, and juices, 50 SECTION VIII. Of fermentation in general, 66 SECTION IX. Of artificial fermentation, 80 SECTION X. Of the nature of Barley, 89 SECTION XI. Of Malting, 94 SECTION XII. Of the different Properties of Malt, and of the number of its fermentable Parts, 113 SECTION XIII. Observations on defective Malts, 131 PART II. SECTION I. Of the heat of the Air, as it relates to the practical part of Brewing, 145 SECTION II. Of Grinding, 157 SECTION III. iv v vi Of Extraction, 160 SECTION IV. Of the nature and properties of Hops, 201 SECTION V. Of the lengths necessary to form malt liquors of the several denominations, 217 SECTION VI. Method of calculating the height in the Copper at which worts are to go out, 220 SECTION VII. Of Boiling, 224 SECTION VIII. Of the quantity of Water wasted; and of the application of the preceding rules to two different processes of Brewing, 230 SECTION IX. Of the division of the Water for the respective Worts and Mashes, and of the heat adequate to each of these, 234 SECTION X. An enquiry into the volume of Malt, in order to reduce the Grist to liquid measure, 253 SECTION XI. Of the proportion of cold Water to be added to that which is on the point of boiling, in order to obtain the desired heat in the extract, 271 SECTION XII. Of Mashing, 286 SECTION XIII. Of the incidents, which cause the heat of the extract to vary from the calculation, the allowances they require, and the means to obviate their effects, 289 SECTION XIV. Of the disposition of the Worts when turned out of the Copper, the thickness they should be laid at in the Backs to cool, and the heat they should retain for fermentation, under the several circumstances, 304 SECTION XV. Of Yeast, its nature and contents, and of the manner and quantities in which it is to be added to the Worts, 311 SECTION XVI. Of practical fermentation, and the management of the several sorts of Malt liquors, to the period at which they are to be cleansed, or put into the casks, 318 SECTION XVII. Of the signs generally directing the processes of Brewing, and their comparison with the foregoing Theory and Practice, 327 SECTION XVIII. An enquiry, into what may be, at all times, a proper stock of Beer, and the management of it in the cellars, 331 SECTION XIX. Of Precipitation, and other remedies, applicable to the diseases incident to Beers, 334 SECTION XX. Of Taste, 342 Appendix, 349 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 vii viii ix x 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 xi xii xiii xiv 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. xv 1 2 3 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. 3 4 5 6 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. 7 8 9 10 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. 11 12 13 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 14 15 16 17 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. 18 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.” 19 20 21 22 23 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 24 25 26 27 28 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...