All substances, then, containing either sugar or starch, or both, will yield spirits. With sugar, the manufacture consists of two processes—fermentation and distillation. When starch is the original source, as is more commonly the case in the distilleries of this country, the first step is to convert it into sugar, or to saccharify it. This is the object of what is technically called mashing, which consists in mixing the materials in a triturated state with water at the temperature of about 160°. It is mostly from barley, oats, and rye that spirits are manufactured; wheat is less used, owing to its cost. Raw grain is ground to meal; malt is only bruised. A certain proportion of malt is always used, even in distilling from raw grain or potatoes, as the diastase of the malt is neces sary to set agoing the saccharine fermentation. After being agitated for two or three hours, the saccharine infusion, called wort, is drawn off from the grains, and cooled. To this wort is now added a certain quantity of yeast or barm, which induces the vinous. fermentation, and resolves the saccharine matter into alcohol and carbonic acid, accom panied by a rise of temperature. Time alcoholic mixture which results is called the wash, and is now ready -for distillation. This takes place in an apparatus called a still, or alembic (q.v.). In its older and simpler form, the still consists of a Copper vessel, into which the wash is put. This vessel is provided with a close head, terminating in a bent tube, which passes, in a spiral form (the worm), through the refrigeratory, tilled with cold water. See STILL. When heat is applied to the still, the spirit begins to rise in vapor at 176°, along with more or less steam; these vapors pass through the worm, become condensed by the cold, and drop or trickle in the form of liquid into a receiver. The product of this first distillation in a simple still is called low wines. This is then redistilled at a lower temperature, in order to deprive it of part of the water and of the fetid oils that had passed over with the alcohol. To obtain great purity and strength, repeated distillation is used.
A great improvement in distilling was invented in 1801 by a workman- of Montpellier, of the name of Adam. By making the vapors arising from the still pass through a series of winding passages, maintained at a determinate degree of heat, and deposit part of their water and other impurities, he was able to obtain from wine a spirit of any required cleanness and strength at one operation. This principle has been adapted, by Pistorius of Berlin (1817), to the distillation of the coarser washes of grain and other materials.
Absolute or anhydrous alcohol (q.v.) cannot be obtained by distillation alone. Rec tified spirit, or spirit of wine, for burning in a lamp, still contains, when of ordinary strength, about 25 per cent of water. Alcohol is considerably lighter than water, its specific gravity being 793 (water, 1000). The stronger any spirit is, then, the less will be its specific gravity; and thus the strength of spirits maybe ascertained by,an instru ment which measures their specific gravity, the aerometer (q.v.) or hydrometer. The
excise of Great Britain has established one degree of strength as the legal standard, and this is called proof. The specific gravity of proof-spirit is 918.6, and it contains nearly equal weights of water and alcohol.
If only alcohol and water passed over in distillation, all spirits, from whatever extracted, would be the same; but this is not the case. Brandy, which is distilled from wine, has a peculiar essential oil derived from the grape, and also some acid; rum is impregnated with an essential oil from the sugar-cane, and with other impurities; malt liquor has the essential oil of barley, etc. It is these essential oils that give to the various spirits their distinguishing flavors. Some of the oils and other impurities are disagreeable and positively noxious; and it is the objects of rectifying to remove these. The mellowing effect of age upon spirits is owing to the evaporation or spontaneous decomposition of the essential oils. Newly distilled spirits are in general fiery, and specially unwholesome.
Sugar, when fermented, resolves itself into nearly equal weights of carbonic acid and alcohol; a pound of sugar, therefore, should yield upwards of half a pound of proof-spirit. The quantity of spirit afforded by different grains depends upon the pro portion of starch they contain: 100 pounds of starch is calculated to yield 35 pounds of alcohol, equal to nearly 8 gallons of proof-spirits. Of the various grains, wheat is the most productive. Taking the average of wheat, barley, rye, oats, and maize, 100 pounds of corn yield 40 pounds of spirit of specific gravity 942 = 3.47 gallons proof. A distiller of malt whisky, says Dr. Ure, calculates on obtaining two gallons of proof spirits from one bushel of malt in ordinary years. The highest yield is 20 gallons per quarter of 8 bushels.
The principal intoxicating beverages produced by distillation are : 1. Brandy (q.v.), which name is applied properly only to spirits distilled from wine. 2. Rum is man ufactured from molasses and other uncrystallizable products of the sugar-cane. 3. Corn or malt spirit, under the various names of British spirits, gin, whisky, etc. The Dutch distillers give a peculiar flavor to their spirits (Hollauds) by adding a portion of juniper-berries to the other ingredients. From the French name of the juniper, genievre, come genera and gin. 4. Spirits from various vegetable substances. In Ger many, a great quantity of spirit is distilled from potatoes, which contain about five per cent of starch. Beet-root and carrots are also used in the same way. The Swedes make a kind of spirit from the sap of the birch, and the maple and other trees are turned to a similar account. We have, besides, cherry-brandy, peach-brandy, cider spirit, etc. 5. Arrack (q v.) is the East Indian name for all ardent spirits. See SPIRITS.