Alcohol does not occur in nature, but is the product of the decomposition of glucose [uncrystallizable sugar], which, under the influence of certain nitrogenous substances called "ferments," is split up into alcohol and carbonic anhydride, the latter being evolved in the form of a gas, while the former remains behind mixed with water, from which it is separated by distillation. All substances containing sugar, or substances which can be converted into sugar (e.g. starch), are "alcoholizable," or capable of yielding alcohol. The manufacture of alcohol on a commercial scale is too large a subject for discussion here, and may best be studied in such works as Spons' • Encyclopaedia (pp. 192-229), but the chief varieties deserve a brief notice. In all cases (except caustic alcohol) the same operations have to be carried out, viz. (1) fermentation, to convert the glucose into alcohol; (2) distillation, to separate the water and alcohol; (3) and these are followed by rectification. Fermentation and distillation are described in another section, but rectification will be discussed at the end of the present article.
This term is commonly applied to sodium ethylate, a product formed by the decomposition of absolute alcohol with pure metallic sodium, the chemical formula being C2 H5. Na 0, or alcohol which has had one atom of its hydrogen replaced by one of sodium.
Dr. Richardson gives the following directions for preparing a solution of the proper strength for use: - Place 1/2 fl. oz. of absolute alcohol in a 2-oz. test-tube surrounded by a water-bath at 50° F. (10° C); add sodium in small pieces to the alcohol so long as gas is given off; then raise the temperature of the bath to 100° F. (38° C), and add more sodium so long as it continues to dissolve; lastly, cool to 50° F. (10° C), and add 1/2 fl. oz. more absolute alcohol. There are several obvious objections to this method, in the time occupied, the long exposure to the air of such hygroscopic bodies, and the varying strength of the product. To remedy these, Dr. L. H. Smith proposes that the solution be made from a weighed amount of sodium, with as little exposure as possible. He finds the average weight of sodium used for making 23 cc. to be 0.635 grm., forming 1.877 grm. of sodium ethylate; this dissolved in 20 cc. of alcohol would give a solution containing 9.385 per cent. To make a 10 per cent, (nearly) solution would need 0.68 grm. sodium for 20 cc. absolute alcohol, and 2.01 grm. of the ethylate in 20 cc.
Dr. Smith prepares a solution of 10,05 per cent, strength as follows: - 20 cc. of absolute alcohol is placed in a test-tube, closed with a perforated cork, into which a small tube drawn to a fine point has been inserted; the test-tube is placed in a bath of ice-water; 0.08 grm. of sodium is weighed out, cut into 3 pieces, and immediately replaced in the hydrocarbon oil in which it is kept; one piece of the sodium is quickly dried of the oil, dropped into the alcohol, and the cork replaced in the test-tube. It rapidly dissolves, when the second piece is added, and finally the third, observing that as the solution becomes stronger and the reaction slower, the test-tube is removed from the bath at intervals, to allow the temperature to rise, and hasten the solution. The finished solution is immediately transferred to small bottles and kept from the light. - (Pharm. J/.,  xii. 995.)
The most important juicy fruit (cereals or grain will be separately considered) affording alcohol is undoubtedly the grape. For this purpose the just ripe unbruised grapes, in bunches, are crushed in perforated boxes, and the exuding juice is collected in vats. The juice and the refuse (" marc") are fermented either separately or together. The resulting alcoholic liquid is distilled to afford genuine brandy or wine alcohol. Among other fruits that have been similarly utilized are apricots, cherries, peaches, currants, gooseberries, raspberries, strawberries, and figs. Acorns, freed from the shells, finely ground, mashed with malt, and allowed to ferment, yield an alcohol said to be equal to that from grain. Horse chestnuts might be turned to a similar useful account.
The cereals contain an amylaceous (starchy) substance, which under the influence of diastase is converted into fermentable sugar. The following table shows the possible yields from different grains: -
Pints pure alcohol.
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Rice, maize, wheat, sorghum, and rye are most largely used; barley and buckwheat are added in some proportions; oats are too dear to be employed for any purpose but lending an aroma to the product of other grains.
The processes necessary to prepare grain for fermentation are: -
(1) Steeping in water for 30 to 40 hours, or until the grains yield readily when crushed between the fingers.
(2) Germination, or spreading the drained grain in beds 2 or 3 ft. thick in a "malthouse," kept at 53 1/2oF. (12° C.); here it heats, and soon begins to germinate ("grow out "), this operation being finished when the rootlets have attained 2/3 the length of the grains, which may require 8 to 15 days. Care is needed in regulating the temperature, and the mass wants turning every 6 to 8 hours before germination, and every 3 to 5 hoars afterwards, the temperature of the grain being kept at 59° to 61° F. (15° to 16° C).
(3) Drying the germinated grain ("malt") in layers of about 12 in. in a " kiln " at a temperature commencing at 95° F. (35° C), rising to 131° to 140° F. (55° to 60° C), and finishing at 176° to 194° F. (80° to 90° C).
(4) Grinding more or less finely.
(5) Mashing the malt and unmalted grain with water at 95° to 100° F. (35° to 38° C), to libeiate the saccharine fermentable matters from the starch of the unmalted grain by the action of the diastase generated in the germination of the malt.
(6) Infusion of the mass by adding boiling water till the temperature reaches 140° to 158° F. (60° to 70° C), then allowing to stand for 4 hours with the heat never below 122° F. (50° C), to convert the liberated starch into glucose.
(7) Fermentation of the "wash," previously cooled down to 68° to 79° F. (20° to 26° C), in covered vats, by adding about 10 1/2 pints of liquid or 7 lb. of dry brewer's yeast for every 250 lb. of grain used, and leaving for 4 or 5 days.
Grain alcohols are chiefly represented by gin and whiskey.
Rich molasses (the impure uncrystallizable sugary product separated from raw sugars by the process of refining) contains as much as 50 per cent, of sugar. The drainings and skimmings obtained on cane estates in the preparation of sugar are included under the same term. When diluted with water, fermentation sets in rapidly. Molasses from beet-' sugars are usually alkaline, and first need acidification, about 4* lb. of concentrated sulphuric acid being added to each 22 gal. of molasses, previously diluted with 8 to 10 volumes of water. Fermentation is hastened by the aid of a little brewers' yeast, or other natural ferment; it begins in 8 to 10 hours and lasts over 60.
Cane-molasses alcohol is familiar as rum, while the beet-molasses article is generally rectified down to almost pure spirit.
Large quantities of alcohol are distilled in Sweden and Russia from reindeer moss (Cladonia [Cenomyce] rangiferind) and Iceland moss (Cetraria islandica). The yield is said to be as great as from good grain, while the supply of material is abundant and cheap.