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ferment; for which purpose yeast and in about a 'month tapped.
duced, which is submitted to the I accordingly procured from a examination of the society. But public-house two gallons of itrong the vessel being broken before the It had a disagreeable bitter distillation was finished, the
quantaite, owing either to bad hops, or tity it would have yielded was not to some substitute for hops. A large ascertained. However, that which part of the liquor was impregnated, was obtained, appeared not to difin Nooth's machine, with fixed air, fer much in quantity from what an which it seemed to absorb very ra- equal portion of common ale would pidly and in large quantity. When have afforded. it was thus impregnated, it was As I had lost my notes, and was mixed with the other part, and obliged to make out the preceding poured into a large earthen jug, account from memory, I designed the mouth of which was stopped to repeat the experiments again ; with a cloth, and placed in a de- bat various engagements prevented gree of heat, varying from 70° to me, till the latter end of August 80°. In twenty-four hours the li- 1784. Of these experiments the quor was in bris fermentation, a following notes are taken from my strong head of yeast began to col- journal : lect on its surface; and, on the August 30, I procured two galthird day, it appeared to be in a lons of common ale wort, two quarts ftate fit for tunning. It was there- of which were, in the evening, im
put into an earthen veffel, such pregnated, but not saturated, with as is used in this country by the fixed air. The impregnated liquor common people as a subititute for was then added to the other part, a barrel, for containing their finall and, about midnight, placed in brewings of fermented liquors. large jug, within the air of the During the space of near a week, kitchen fire, where it remained previous to the stopping up of this during the night. In the morning vessel, much yeast was collected on no signs of fermentation. At five its surface, and occafionally taken o'clock P. M. only a flight mantling off ; and by means of this yeast, on the iurface. Apprehending the I fermented wheat. Alour, and pro- quantity of gas to have been too cured as good bread as I couid have smali, a bottle, with a perforated obtained by using an equal quan- stopper and valve, containing an tity of any other yeast.
effervescing mixture of chalk and The vessel was now stopped up; vitriolic acid, was let down into
the wort. At nine o'clock, the dif- in which the yeast had been collectcharge of air, from the bottle, was ing from so small a quantity of going on briskly, and the wort liquor, its fermenting power might ieemed to be fermenting. At eleven have been expected to have been o'clock the bottle was withdrawn, impaired. the fermentation being commenced September 5th, the liquor was beyond a doubt ; the surface of the again covered with a plentiful head liquor having a pretty strong head. of yealt; and the fermentation was Temperature of the wort 80°mat suffered to proceed to the 12th, the outside of the vessel 78o. when the vessel was closed, in the
September ift, seven o'clock, usual manner. A. M. the fire having been low [ intended, in a few weeks, to during the night, the fermentation have committed the liquor to difwas less brisk - temperature of the tillation ; but my thoughts were wort reduced to 72, and probably unfortunately directed to an object had been lower during the night, which engaged my moft anxious as the fire was now increased. The attention; and my wort was neliquor was stirred up, placed in a glected till the latter end of Februsituation where the thermometer ary ; when, on tapping the vessel, pointed to 82°, and the effervescing the liquor, from having been kept mixture was again immersed. It so long, under such disadvantageous was withdrawn at noon, and the circumstances, and, perhaps, from thermometer ftanding at 92°, the too great heat in the fermentation, wort was removed farther from the and the too long continuance of it, fire-At four o'clock, P. M. the had passed from the vinous to the head of yeast was strong, and at acetous Itate, and was become exeleven o'clock was increased. cellent alegar.
September 2d, nine o'clock, As I had obtained a vinous fpiA. M. the liquor was judged to be rit from the former parcel of wort, in a proper state for tunning. It I was not forry for this event, as it was accordingly removed into the was going a ftep farther than I exvessel before described, and carried pected. For I had now obtained into the cellar at eleven-at noon, yeast, bread, ale, ardent spirit, and a high head of yeast was running acetous acid. A specimen of the over the top of the veffel--fome of last is now produced to the fociety. it was taken of, and in two hours I flatter myself that these expe. the head was equally strong. riments may be of extenfive utility,
September 3d, the fermentation and contribute to the accommodaproceeded regularly this day; and tion, the pleasure, and the health of on the 4th I had collected fo much men, in various situations, who yeast as to make a loaf with it, have hitherto, in a great degree, which, when baked, weighed about been precluded from the use of fertwo pounds. The loaf was well mented liquors ; and be the means fermented, good bread, having no of furnishing important articles of peculiar taste, except a flight bit- diet, and of medicine. Not only terneis, proceeding from the wort at fea, but in many situations in having had too large a proportion the country, and at particular seaof hops. Though, from the time fons, yeast is not to be procured.
By the means I have suggested, in a liquid state. A due degree of
. If the contrivance. This discovery there. process has been too slow, and the fore may, perhaps, be of no small degree of heat insufficient, the liutility in public breweries, and I quor will be flat and spiritless; but would recommend it to the atten. if these have been too rapid and extion of persons concerned in the ceflive, it will pass into the acetouş brewing trade.
fermentation, to which indeed it is Let us now proceed to describe continually tending. But the more the circumstances necessary to, and ardent spirit is generated, the less the phenomena attending fermen- speedy will be the change to the tation, as described by chemical acetous state. writers, and then endeavour to During the progress of the aceform fome theory which may ac tous fermentation, which will even count for them.
proceed in closely stopped vessels, Sugar, the juices of ripe fruit, no separation of air is observable, and malt, are all more or less dis nor any itriking phenomena. The posed to run into fermentation. But liquor gradually loses its vinous before this can take place, it is taste, and becomes four, and a grofs necessary they should be diluted sediment falls to the bottom ; while with water, so as to bring them to a quantity of viscid matter till re
* London, 1781.
mains, enveloping the acid, which faccharine, united to much viscid may be separated from much of the mucilaginous matter. impurity by distillation.
2. If nitrous acid be added to The progress of these processes is fugar, the inflammable principle of accelerated by the addition of fer- the latter is seized by the acid ; the ments, to the action of which it has whole, or at least one of the conbeen supposed neceflary, that they fituent parts of which, is thereby fhould have passed through the state converted into nitrous gas, and flies of fermentation into which they are off in that form. By repeated afintended to bring the liquor to fusions of this acid, more gas is which they are added; and that it formed, and the remainder of the was not possible to bring the fari- sugar is changed into crystals, hav. naceous infusions into the vinous ing the properties of an acid, lui fermentation without the aid of generis, and which has been dematter already in that state. This nominated, by Bergman, sacchathe preceding experiments have rine acid. proved to be an ill-founded notion, 3. Saccharine acid is resolvable as it appears that fixed air, obtain- by heat into some phlegm, a large ed from calcareous earth by means quantity of inflammable and fixed of acids, produces the effect, as air (both of which contain latent perfectly as when the ferment has heat) and into a brownish refiduum, been taken from a fermenting li- amounting to to of the weight of quor.
the acid. Fixed air is supposed to In fermentation, it is said, new consist of pure air united to phlo. arrangements take place in the par- giston ; and inflammable air, to be ticles of the liquor, and the proper- almost pure phlogiston. ties of the substance become differ 4. Water is found to be formed ent from what it before possessed. by the union of pure air, and inBut what these arrangements are, flammable gas, deprived of their or how these properties are changed, latent heat; for, if these two elaftic we are not told. Dr. Black, I am fluids be exploded together, in a informed, declares he is unacquaint- close vessel, over mercury, the whole ed with any satisfactory theory. is converted into water of the same
But perhaps facts, especially some weight as that of the air and gas late chemical discoveries, may throw jointly. In the process much heat light on the matter, and enable us is evolved. Again, if water, in the to advance fome conjectures that form of steam, be forced to pass may tend, at lealt, to lay the foun- through' a tube, containing iron dation of a theory.
Thavings, strongly heated, the wa1. Sugar is an essential salt, con ter, according to Messrs. Watt and taining much oily, viscid matter. Lavoisier, is decomposed; the phloDuring its combustion it repeatedly giston passes off, united with heat, explodes ; a proof that it contains in the form of inflammable gas, not only much inflammable matter, while the humor, or dephlogisticated but also a quantity of air. Malt is water, unites to the calx of the
* Bergmani Opuscula Chemica, Vol. I. Art. de Acids Sacchari,
métal, from which it may be again parts of the matter are feparated; obtained, in the form of pure air, and the particles of the component or of äerial acid, according to the principles being by this means degree in which the calx has been placed beyond the sphere of their dephlogisticated. It has been al- mutual attraction, begin to repel. ready observed, that faccharine each other. A large quantity of inatter cannot be brought to fer- phlogiston is discharged, together ment without water.
with some pure air. The greatest 5. A vinous liquor, on distilla- part of the inflammable principle tion, yields an ardent spirit. enters into a new combination,
6. Spirit of wine has had the joining the phlogistic part of the whole of its inflammable part dif- water, and, in proportion, feparatsipated by combustion ; after which, ing from it the pure air, while anoMr. Lavoisier found the watery part ther, but much smaller portion, increased in weight, from sixteen to uniting in its nascent state with eighteen ounces, by the absorption this pure air, forms fixed air; which, of the air, decomposed by the com in its attempt to escape, carries up bustion.
with it much of its viscid confine7. The residuum, after the distil- ment. In the conversion of the pure lation of ardent spirit from fer- into fixed air, a confiderable porinented liquors, is acid.
tion of heatis rendered fenfible. And 8. Mr. Lavoisier has supposed this heat contributes to the farther pure air to be the acidifying prin- decomposition of the faccharine ciple of all the acids; and that their substance. The viscid matter coldifference from each other confifts lecting on the surface, prevents the in the basis united to this pure air. escape of too much of the gas, and
As our experiments were made promotes its re-absorption, that with an infusion of malt, and with thereby the brick and agreeable fixed air, employed as a ferment, taste of the liquor may be formed; let us endeavour to account for the while the infammable principle, several phenomena and results of accumulating and becoming confermentation, as appearing in these densed in it, forms the ardent experiments.
fpirit. The wort being impregnated with Thus a decomposition of the fixed air, and placed in such a fitua. water takes place, somewhat similar tion as to bring it to the degree of tò what Mr. Watt has fupposed in heat, at which wort is commonly the production of pure air from mixed with yeast, the gas for some nitre. The nitrous acid, feizing time remains in a latent or quiescent on the phlogiston of the water, deftate ; but, from its tendency to phlogisticates the humor or other recover its elastic form, aided by part of the water, which, comheat, it presently begins to burit bining with the matter of heat, from the bonds in which it was con- paffes off in the form of pure air. fined. By this effort the mucila The vessel being stopped, some ginous parts of the infusion arë at. of the faccharine matter being not tenuated; the faccharine matter is decomposed, the liquor will condeveloped; and, the same cause tinue to have a sweetish taste. But, continuing to act, the constituent the fermentation still going on, in