Alcohol is derived directly from fruit sugar, and indirectly from
starch. The grains, as wheat, rye, corn; and potatoes, supply starch
most economically. The starch in these substances is converted into
glucose by heating with very dilute sulphuric acid, or by fermentation
with malt. Glucose is further acted upon by yeast containing the Torula
cerevisiae, which converts 15 per cent of glucose into alcohol and
carbonic dioxide. The weak alcohol resulting is subjected to repeated
distillation until sufficiently pure and concentrated. In the natural
fermentation of fruit sugar in grape juice, during the formation of
wine, the amount of alcohol is self-limited to 15, rarely 20 per cent,
since the ferment is killed by a larger amount of alcohol than this.
DERIVATION.--The official alcohol is derived from rectified spirits, by
maceration, first with anhydrous potassium carbonate, then freshly fused
calcium chloride, and finally by distillation.
PROPERTIES.--A liquid composed of about 92.3 per cent, by weight, or
94.9 per cent, by volume, of ethyl alcohol (C₂H₅OH) and about 7.7 per
cent, by weight, of water (U. S. P.). A transparent, colorless, mobile
and volatile liquid, of a characteristic rather agreeable odor and a
burning taste. Specific gravity about .816 at 15.6° C. (60° F.).
Miscible with water in all proportions and without any trace of
cloudiness. Also miscible with ether chloroform. It is readily volatile
at low temperature, and boils at 78° C. (172.4° F.). It is inflammable
and burns with a blue flame.
DOSE.--Horses and cattle, 1 to 3 oz.; sheep and pigs, 2 to 4 dr.; dogs,
1 to 2 dr. Diluted four to six times its bulk of water.