The American Practical Brewer and Tanner

by Joseph Coppinger

There is a great similarity of appearance between the two species of low combustion, fermentation and respiration. Fermentation, like respiration, is the spontaneous effort of involuntary motion to decomposition; and in the fermenting mass, as in the animal system, it raises the temperature of both above that of the surrounding atmosphere: that is, it is the cause of heat and involuntary motion, both in the fermenting mass and in the animal system; and, like slow combustion, consumes both, and resolves them into their first principles, from which tendency the latter is constantly withheld by the ingesta, fuel, or food, thrown in. I am well aware I must not carry this reasoning any further.

Deep investigation may be thought not to be the object of our research; but we must always have two things in view in inquiries of this nature; indeed, in every pursuit of useful knowledge, where, like the present, it is connected with the first principles, to pursue the winding path of nature, through all her meanderings, up to the ultimate source of these elements, which are the instruments of her operations; and when we are favoured with a knowledge of these, either as the reward of laboured assiduity and attention, or the result of chance, to copy the original as close as we can.

I know I shall be justly accused with tautology. I must plead guilty to the charge, not having leisure to apply the pruning hook of correction. The misfortune is, that new doctrines must appear in a new dress, by which they wear the garb of novelty, though, with respect to first principles, there is nothing new under the sun; yet the application of these principles might have remained in oblivion for ever if not called into action. The man who in an age calls them into action, and beneficially applies them for the good of that community of which he is a member, may be virtually, though not literally, called the discoverer of a principle. The man that projects, and the man that executes a voyage of discovery, have superior claims to the man at the mast head who first cries out land. The new turn that the discoveries of modern philosophers has given to natural philosophy, requiring a change of names as well as system; unusual words are unavoidably introduced to express new terms of science, which gives a different character and fashion to the whole, that I should have great pleasure in avoiding, were it possible, which it obviously is not, finding it easier to glide down the stream than oppose its torrent.

Notwithstanding that I have calculated upon nineteen pounds only of twenty-five pounds per barrel of fermentable matter being attenuated, and have even in that quantity included five pounds eight ounces of lees and yest, (the least quantity produced,) such calculation must not be admitted to preclude the practicability of attenuating almost every particle of fermentable matter, and replacing it with an equivalent particle of spirit, if that spirit which is now carried off by the avolation of the fixed air, is, agreeably to my proposal, either arrested in its flight, or filtered, after its escape from the guile tun and cleansing vat, by the proper apparatus.

Having in a former part of these papers observed, that attenuation may be carried too far, it may be necessary for me to reconcile these seemingly opposite positions, which should be understood in this way: When the quantity of fermentable matter, suspended in a barrel of worts, intended for beer, or ale, is from five to ten pounds more than twenty-five pounds per barrel, every particle of it may be safely attenuated, as the quantity of spirit generated will be sufficient to preserve the beer, or ale, for any requisite length of time, provided it has been properly hopped, &c., or in lieu thereof, received certain other additions to improve its vinosity, strength, and keeping; when the quantity of fermentable matter in worts is from five to fifteen pounds per barrel less than twenty-five pounds, the height of the attenuation ought to be limited on keeping beer and ale; the spirit generated being insufficient to preserve so much fermented fluid in a drinkable state for any length of time, with the usual additions only, even during the summer heats of our own climate; and if so, it is totally unfit for either exportation to warm latitudes, or for keeping at home.

For the right understanding of these observations, we should consider that the unattenuated fermentable matter is perpetually furnishing a gradual supply of fixed air and spirit, by means of the imperceptible fermentation always going on in vinous liquors.

Weak beers and ales fret and spoil very soon in warm weather, which proceeds from the development and avolation of their fixed air; strong beers and ales have their limits under the same influence of heat, time, change of the atmosphere, &c., and owe their preservation to two things, viz. to a due proportion of fermentable matter unattenuated, or the quantity of spirit they contain; as under these circumstances they are either preserved by the spirit already formed, or that continually supplied by the spontaneous decomposition of the fermentable matter they contain, slowly developing and yielding a fresh supply of air and spirit; hence beer and ales, not too highly attenuated, derive strength and spirituosity from age, when properly stored or cellared, and duly secured from the changes of the atmosphere.

These observations are applicable to sweets, or made wines, and to those which are the produce of the grape, the progress of fermentation and attenuation being (or ought to be) interrupted in them by racking off, which is similar to cleansing in beers and ales: and in Madeiras, and other dry wines, the incipient acidity is corrected and restrained, by proper additions introduced in the early part of the process, and with others of similar effect when the wines are making up, either for use or exportation.

We may gather from these observations, that worts attenuated for beer or ale, to the decomposition of all their fermentable matter, that is, attenuated so high, or so low, that their specific gravity is reduced to the standard of common water, and from that to the degree of levity spirit is known to give to water, in the proportion to the quantity added, and left to the preservation of the spirit formed, they have little or no auxiliary assistance from their original products, already exhausted by the highest or completest attenuation obtainable; an important circumstance, always to be attended to, particularly by those who affect an unnecessarily high attenuation!

The intelligent brewer may, by the assistance of these observations, form a most accurate rule for the regulation of his future conduct in the management of fermentation, according as his beer or ale is to be weak or strong, or for present use or long keeping; for the accomplishment of which, the use of the hydrometer and thermometer claim his peculiar attention, and will undoubtedly answer his expectations, when joined to the certainty he is now at, of knowing when he is, or is not, to expect the development of fixed air and additional spirit, by which he can govern himself accordingly.