When the carbonic acid gas, or fixed air, so often mentioned in these papers may be rendered subservient to part of the improvements I have in view, and which is the constant, abundant, and uniform result of low combustion, or vinous fermentation, in proportion of thirty-five pounds weight to every hundred of saccharine or fermentable matter, fermented in a due proportion of liquor, or water; from the decomposition of which last, and the absorption of its oxygen, it is principally obtained.

We have previously seen that one hundred pounds of fermentable matter consists of eight pounds of hydrogen, twenty-eight of carbon, and sixty-four pounds of oxygen; we have also seen that about thirty-five pounds of carbon is extricated and detached from this quantity of fermentable matter, properly diluted in water during fermentation; allowing the usual quantity of spirit at the same time to be formed by the process of this superfluous carbon, (as it now appears) must come principally from that decomposition of the water of dilution, and not from saccharine matter employed, which contains altogether but twenty-eight pounds of carbon, the whole of which must necessarily go to the formation of the fifty-seven pounds of dry alcohol produced.

But not to descend too deeply into particulars that might lead into discussions not absolutely necessary in this place, let us take the produce of ten gallons of ardent spirit, at one to ten over proof. We here find that much more carbon has been generated, and given to the atmosphere, than went to the composition of this quantity of spirit, independent of the large quantity of alcohol dissolved in, and carried off by it, in its flight as before observed.

Allowing the average quantity of fermentable matter in a quarter of malt, barley, or other grain, to be only seventy-five pounds, then four quarters will be equal to three hundred subtile pounds of raw sugar; or eighty quarters of the one will be equal to six thousand pounds of the other, or three tuns weight of unadulterated molasses.

If we estimate the superfluous carbonic acid gas of this quantity of materials at only twenty-eight pounds per hundred, that will be sixteen hundred and eighty pounds dissipated during the fermentation, which is a loss, on every brewing of this quantity of materials, of upwards of forty-one gallons of spirit, of the strength of one to ten.

What is computed here in spirit, may easily be applied to wine, porter, beer, ale, sweets, &c. In barrels allowing three gallons and three quarts of spirit per barrel to the former, and four gallons per barrel to the latter, which gives eleven barrels and three quarters of the one, and ten barrels and a quarter of the other, lost on each brewing of eighty quarters of malt, or the average of that quantity of other materials, by the mismanagement of the fermentation in one point only.

It must appear evident to every person capable of investigating this calculation, that every six or seven pounds of carbon, fixed upon each quarter of malt, or other materials, there will be an augmentation of gravity or strength on this number of quarters, of ten or twelve barrels each brewing; that is, every six or seven pounds of this fugitive carbon that we arrest and fix in the fermenting fluid, as a component part of the subsequent produce, by presenting the requisite portion of oxygen and hydrogen, for the purpose within the sphere of each others attraction, we increase our strength in the before-mentioned ratio. It is of little moment whether this redundant gas comes from the water of dilution or from the fermentable matter, as under, if we can by any means turn it to account.

We have presumed the average quantity of fermentable matter at seventy-five pounds per quarter; this must be evidently on the best goods; this will give us a length of three barrels per quarter of malt of eight bushels, of twenty-five pounds per barrel, specific gravity. Suppose the apparent attenuation of these goods to be nineteen pounds, the transparent gravity will be six pounds per barrel, viz.

Gravity of the worts in the cooler just before letting down into the guile-tun, per barrel, 25 lb.
Apparent attenuation per barrel, down into the guile-tun, per barrel, 19 lb.
Transparent gravity per barrel, down into the guile-tun, per barrel, 6
25 lb.
Or take it as it really is, viz. specific gravity per barrel, 25 lb.
Real attenuation per barrel, 13 lb. 8 oz.
Yest and lees, 5 8
19 lb.
Gravity per barrel, when transparent, 6
25 lb.

It may be said that nineteen pounds is the real attenuation, and the yest and lees produced is part thereof, as the fluid, or beer, in a state of transparency is but six pounds per barrel specific gravity, and it may, in some degree, be allowed to be so, as there is really so much gravity lost during the process of fermentation. If we multiply thirteen pounds eight ounces, which I have called the real attenuation, by four, we shall find the result to be fifty-four pounds, which is nineteen pounds more of superfluous gas upon four barrels of worts, of twenty-five pounds gravity each, than is extricated from an equivalent quantity of saccharine matter; that is, from one hundred pounds of raw sugar or one hundred and twelve pounds of molasses, and their respective waters of dilution, when the yest and lees do not exceed five pounds eight ounces per barrel. This may be truly called an analysis of the fermentable matter, giving the component parts tolerably exact; though much depends on the management of the fermentation, and the subsequent cleansing. By this analysis it appears, that the mucilage of malt, or grain, gives out more gas than the mucilage of sugar; and leaves a doubt on the mind whether to adjudge the superfluous gas to the fermentable matter, or to the water of dilution, or partly to both; but so it is, that these are the products, whatever source we derive them from, and there is no denying facts. The yest first added is not brought into this account.