Alcohol possesses the power of dissolving a largo number of substances insoluble in water and acids, such as many inorganie salts, phosphorus, sulphur, iodine, resins, u,sential oils, fats, colouring matters , &o. It precipitates albumen, gplatiue, starch, gum, and other substances from their solutions. These properties render it an invaluable agent in the hands of the chemist.
Alcohol is found in, and may bo obtained from, all substances—vegetablo or other—which contain sugar. As stated above, it does not exist in those in the natural state, but is the product of the decomposition by fermentation of the sacoharine principle contained therein ; this decomposition yields the spirit in a very dilute state, but it is readily separated from the water with which it is mixed by processes of distillation, which will subsequently be described. The amount of alcohol which may be obtained from the different unfermented substances which yield it varies consider ably, depending entirely upon the quantity of sugar which they contain.
The following are some of the most important sources of alcohol which have been employed in Europe ;—Grapes, rice, beet-root, potatoes, carrots, turnips, molasses, and grain. On the continent, many fruits are used for the production of alcohol besides the grape, such as apricots, cherries, peaches, currants, gooseberries, raspberries, strawberries, &c.; figs, too, are used extensively in the East. In America, nearly the whole of the spirit of commerce is obtained from potatoes, Indian corn, and other grains. In India, Japan, and China, rice and sorghum arc the chief sources. Among a variety of other substances which have been and are still used for tho production of alcohol in smaller quantities, are roots of many kinds, such as those of asphodel, madder, &c. Seeds and nuts have been made to yield it ; and even woody fibre, old linen, cotton, and hemp have been successfully converted into cellulose, sugar, and thence into alcohol. It will thus be seen that the sources of this substance are practically innumerable ; anything, in fact, which oontains or can be converted into sugar is what is termed " alcoholisable." Alcohol has become a substance of such prime necessity in the arts and manufactures, and, 111 one form or other, enters so largely into the composition of the common beverages consumed by all classes of people, that its manufacture must, of necessity, rank among the most important industries of this and other lands. The traffic in spirituous liquors in this country has during the last few years developed, and is still developing, rapidly; and with the demands of an increasing population it is reasonable to expa et that a still further impetus will be given to the production of NN illCO and spirits in England. The manufacture of ale and porter is confined to our own
country, and forms the staple industry in some extensive districts, where it gives employment to many thousands of men, and handsome profits to the manufacturer. The production of whiskey is also monopolised by Great Britain, the Scotch aud Irish distilleries supplying the entire demand for this article. Wines, brandy, and liqueurs are not produced in any quantity in the British Isles.
FERMENTATION.—Fermentation is a spontaneous change undergone, under certain conditions, by any animal or vegetable substance under the influence of ferments, by which are produced other substances not miginally found in it. There are several kinds of fermentation, the most important being that by which alcohol is formed from glucose, or alcoholic fermentation. If this process be not carefully conducted, other fermentations ensue, resulting in the formation of acetic, lactic, and butyric acids, and sometimes of saccharine and viscous matters, which are productive of much annoyance to the distiller. These may be called the accidents of fermentation, and must be very carefully guarded against.
Glucose is said, therefore, to be subject to four principal kinds of fermentation—alcoholic, acetous, lactic, and viscous. There are others of a less important nature to which glucose is liable, but only the above four will be examined in this article.
The real nature of the process of fermentation, though it has been made the subject of much in vestigation, is still shrouded in a good deal of obscurity. Many theories have been put forward to account for it, of which the most probable is that of M. Pasteur, who tells us that the action of ferments is due to the life and growth of the minute cells of which they are composed. To effect this development, the cells require mineral food, and if this be withheld, no fermentation can take place. M. Pasteur has shown this by placing a small quantity of brewer's yeast, the ferment commonly employed in industrial operations, in an absolutely pure solution of sugar. He observed no sign of fermentation until he had introduced a soluble phosphate and a salt of ammonia, salts which constitute the mineral components of the ferment. The presence of alburninoicl matters appears also to be indispensable; but these are contained in the ferment itself, so that in case the liquor is not sufficiently provided with such matter, the ferment will, so to speak, nourish itself with its own substance, throwing off at the same time the useless particles that are not necessary for its own growth. The results of careful microscopical examinations of the minute cellules of which yeast is composed fully bear out M. Pasteur's view of the subject.