or it ought to form very nearly equal weights of each of these constituents.
This explanation of fermentation, though in some points hypothetical, must be admitted to approach pretty nGar the experiments made upon the subject. These experiments are attended with so much difficulty, that rigid accuracy cannot be expected. In all likelihood, we can never arrive at the truth by any other method than that which we have followed upon this occasion. Nor will this method be any longer doubtful, as soon as it is ascertained with pre- 0 cision, that sugar can be resolved into alcohol and carbonic acid, and as soon as we know the proportions of the two substances evolved. We conceive that both Lavoisier and Thenard have stated the quantity of carbonic acid too low, from not being aware that the whole of the sugar is never decomposed by fermentation. This we conclude from some experiments of our own, made on a large scale, of which we shall now proceed to give an account.
We have given the preceding details to make the reader aware of the chemists to whom the discovery of these important facts is owing. But the following mode of stating the case, for which we are indebted to Liebig, will probably be more easily understood.
1. Glucosin or starch-sugar is composed of 12 atoms carbon, 12 atoms hydrogen, 12 atoms oxygen, and 2 atoms water. Let us represent these atoms by Ci2 Hi2 0i2 +2 (HO).
2. Alcohol is composed of 4 atoms carbon, 5 atoms hydrogen, 1 atom oxygen, and 1 atom water, represented by C4 H5 0 + H 0.
3. Carbonic acid is composed of 1 atom carbon and 2 atoms oxygen, represented by C O2.
Alcohol, . Cl H8 O2 2 Carbonic acid, C1 O4
Thus, every atom of glucosin decomposed, is resolved into 2 atoms alcohol and 2 atoms carbonic acid.
Nine different brewings of pure malt were made. The worts were weak, and they were fermented as strongly as possible by means of large quantities of yeast, added at intervals, as is practised by the distillers. The following table exhibits the specific gravity of these worts before and after the fermentation was over:—
Specific Gravity of the Wort.
Specific gravity of Wort after fermentation.
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