Alcohol

a term popularly applied to the substance which imparts to fermented and distilled liquors an intoxicating property. In modern chemistry the word has a much wider meaning, being applied to a very numerous class of substances, in many members of which the properties characteristic of ordinary alcohol are conspicuous by their absence. Chemically, an alcohol may be defined as a neutral compound composed of the three elements, carbon, hydrogen, and oxygen.

Alcohols are found as natural constituents of many vegetable and animal products, such as certain oils, fats, and waxes. Some alcohols are liquids, while others are solids. So-called ethyl alcohol, or "spirit of wine," is formed in the fermentation of solutions of sugar. When yeast is added to a solution containing grape sugar or glucose, the liquid soon has the appearance of boiling. A fundamental change takes place in the sugar whereby it is broken up into alcohol and carbon dioxide. The process is called fermentation. Yeast alone cannot ferment cane-sugar. The cane-sugar must be first decomposed into fermentable sugar, as grape sugar or fruit sugar; and this decomposition is effected by a substance known as invertase, which invariably accompanies yeast. The ordinary method of obtaining alcohol is to form a thin paste of crushed potatoes, finely ground grain, or of any vegetable material containing starch. The starch is first changed into sugar by the action of malt, then fermentation is produced by the addition of yeast.

Commercial alcohol is never pure, but usually contains from five to ten per cent of water. By careful redistillation the amount of water may be reduced to about two per cent, and this can be removed by adding quicklime, which unites with the water. The liquid which is poured off is distilled again, thus forming approximately pure or absolute alcohol.

Pure alcohol is a mobile, colorless liquid with an agreeable ethereal odor. It has a strong affinity for water, which it readily absorbs from the atmosphere. It mixes with water in all proportions with marked contraction and rise in temperature. The maximum contraction is obtained by mixing 52 volumes of alcohol with 48 volumes of water, the volume of the mixture being 96.3 instead of 100. Pure alcohol boils at 173 degrees Fahrenheit under one atmosphere pressure, and freezes at 202 degrees below zero. It burns with an intensely hot, pale-blue, non-luminous flame. It has a specific gravity of 0.7938 at 60 degrees temperature; in other words, its weight is about eight-tenths as much as water. The amount of alcohol in a mixture of alcohol and water is determined by means of a special form of hydrometer, called an "alcholometer," the scale of which gives directly the per cent by weight or volume for a given temperature, usually 60 degrees Fahrenheit. The point at which the instrument sinks in pure alcohol is marked 100; a similar point for pure water is marked 0. When placed in a mixture, the instrument sinks to a point intermediate between these marks according to the relative proportions of water and alcohol.

Investigations have shown that 100 pounds of the following products of the farm will produce industrial alcohol in the following quantities: Rice, 6 gallons; rye, barley, spelt, corn, and sorghum seed, 5 gallons; Irish potatoes, 1 1/2 gallons; cassava, 2 1/2 gallons; turnips, 4 to 5 gallons; artichokes, 1 1/4 gallons; sugar beets, 2 gallons; sorghum or sugar cane, 1 gallon; waste molasses, 6 gallons; grapes, 2 1/6 gallons; bananas, 1 3/5 gallons; and other fruits from 1 to 1 1/2 gallons. The average range of the alcohol content in various fermented and distilled liquors may be stated as follows: Beers, ale, and porter contain from 2 to 6 per cent of alcohol; wines from 8 to 20 per cent; brandy, whisky, and rum from 45 to 55 per cent.

Alcohol is extensively used in the preparation of lacquers, varnishes, dyes, flavoring extracts, and pharmaceutical preparations. It hardens animal tissues and is destructive of most forms of bacteria. These facts make it a valuable preservative for specimens of natural history. It is occasionally of great value in medicine, and in certain emergencies, where prompt stimulating action is demanded, it is indispensable. On account of its low freezing point, it is used instead of mercury in thermometers intended for measuring low temperatures.

Wood alcohol is obtained by the careful heating, or so-called "dry distillation," of hardwood-beech, maple, or birch-in iron retorts. The aqueous distillate contains the wood alcohol mixed with acetic acid and some minor ingredients, and is known as pyroligneous acid. Tarry matter and other substances separate out on standing and are then removed. The acetic acid is combined with lime and the wood alcohol purified by fractional distillation and other methods. Wood alcohol boils at 150.8 degrees and burns with a blue flame. It can be used for many of the purposes for which the common ethyl alcohol is used, but on account of its poisonous properties it cannot be used in foods and beverages.

Denatured alcohol is ethyl alcohol rendered unfit for drinking by the addition of a substance having a disagreeable taste or odor. Methyl alcohol and benzine are the denaturing agents authorized by the United States commissioner of internal revenue. Ten parts of wood alcohol and one-half part of benzine are added to 100 parts by volume of ethyl alcohol of not less than 90 per cent strength. In Germany, in addition to wood alcohol, a certain amount of pyridine (bone oil) must be added. This gives a denatured alcohol of a very offensive odor, but does not render it unfit for many commercial uses. Other substances have been proposed for denaturing, some of which are the following: gum shellac, camphor, turpentine, acetic acid, aniline blue, castor oil, carbolic acid, caustic soda, and musk.

See Arrack; Absinthe; Pulque; Toddy; Brandy; Cognac; Wine; Beer; Cider; Ale; Whiskey; Sugar; Starch; Distilling; Brewing; Bacteria

JULIUS HORTVET.