FERMENTATION. This is effected by adding either brewer's or compressed yeast to the wort prepared as described above; or to a saccharine liquid obtained from molasses, beets, or other fruits or vegetables. Eight to len parts of brewer': yeast are mixed with 1000 parts of grain mash, and with a larger propor tion of yeast for potato mash. The ehendeal processes involved in fermentation, by which the sugar is resolved into carbon and alcohol, are discussed under YRAsT and FERMENTATION. From three to nine (lays are consumed in fermentation. The process is continued until the density of the liquid ceases to lessen, as indicated by the saccharometer. Hydrofluoric acid is quite gen erally used in the fermentation process. Sadder states, in his holustrio/ organic Clotolstry (•Nvw t lk, Izstui). that the advantages are thinned for its 11.e: by presenting the It--i•tint lu secondary fermentation the alco holic is increased: 121 this yield is (-pet billy maintained sslien raw materials of somewhat inferior quality are used. \then. with out the hydrofluoric acid, the yield would he dinuini.hcd; (3) the development of loauning iii the fermentation is largely In making spirit from beets. sulphuric acid is used during the fermentative process. Much of the beet-spirit is made from molasses derived as a by-product from the manufacture of beet sugar. But in France it is customary to make inn rimt beets directly into spirit. only a small quantity of yeast is required, and fermentation is completed in about twenty-four hours. In the \Vest Indies, the molasses produced in making cane-sugar is utilized in the manufacture If ss hisky. (See \Villsii.Y.) The addition of )east to the saccharine liquid is unnecessary, be tause enough nitrogenous Matter is pres•nt in the inola.sses to produce spontaneous fermenta tion.
Insritt.trioN. The operations thus far tle ,eribed are merely preliminary. They differ from those employed in the two fermentation industries. \vim. and beer making, in that in preparing the for distillation the fermenta tion process is carried to its furthest limit in orill-r tD produce the greatest possible amount of alcohol. The liquid thus prepared for dis tillation is teelmieally known as the trosh. The still is the apparatus in wide!' the wash is re duced to vapor and then condensed. In its oldest and simplest form the still consists of a copper vessel, provided with a closed head, connected with a spiral tube, called the worm. 'Hie latter is placed in a refrigeratory, or closed. chamber, through svhiell cold water is constantly passing. \\lien heat is applied at the still the spirit begins to rise in vapor, along with more or less steam: these vapors pass through the worm, Leconte condensed by the cold, and drop or trickle down into the receiver. The product of the first distillation ill a simple still is a weak and impure liquid teelinically known as low trim .s. This is then rodiatillod at a lower tem perature to deprive it of the water and of the fetid oils which have passed with the alcohol.
In 1801 the first great improvement in was invented by a workman of Montpellier named .1dain. Ily making the vapors rise from the still through a series of winding passages, maintained at a determinate degree on heat, and deposit part of the water and other impurities. he was able to obtain from wine a spirit of any required degree of purity at one operation. 'lids device was applied by l'istorins to the distilla tion of washes made from grains. \•illiin recent sears many inventions have been made to pro duce the purest and strongest alcohol at the lowest possible cost. Sadtler divides the Iliffer eta forms of distilling atpparatus into live gen t classes: (1 ) The simple stills already de scribed, with worm-condenser heated by direct tiring. I 2 / The stills with closed 'wash warmer.' This is a device for saving fuel by causing the pipe eontaiiiiig the hot vapors on their way to the refrigerator coil to its through a vessel containing the wash. Thus the wash is heated to a considerable degree before it enters the still at all (3) Stills with rectifying 'wash•marincr: This a device invented by Dorn, in which the e-›(•1 through which the di` ided into two inents by a sheet of copper. The upper and larger compartment serves as a wash-warmer. Through it the tube conveying the vapors from still passes into the lower compartment, where at first the distillate is condensed. IIIIt as the wash is warmed by the vapors from the still, the distillate in this compartment gives oil alcoholic vapor: which pa,, uu and are ettildensed in the worm, while the watery portion is allowed to run hack into the still. This rectifying action' can he inereased by intro ducing two or more chambers between the still and the final condenser. 1II Mills with wash
warmer, rectifying, and dephleginator apparatus for intermittent working. 151 Stills with similar apparatus for A dephlegmator is an apparatus for partially con densing the vapor. hy mesas of metallic dia phragms. The vapor, coining in contact with these metallic sheets, is (Milled. and the watery portico', which condenses most readily, separates and flows back. while the alcoholic vapors pass on through the pipes to the condenser. The l'istoritis apparatus. already referred to, is an intermittent dephlegmator, The original inven tion has been improved successively by Gall. Schwartz, and Siemens, and is much used in Ger many in making potato spirit. Examples of the fifth class of stills, those with a continuous dephlugmatur apparatus. are the Coffey still. Used iii England for making grain spirit, and the Savanc still, used in Franc• in distilling brandy. The Coffey still is particularly well adopted to the manufacture of what is known as 'silent spirit,' that is a spirit which is very strong and pure, but nearly destitute of flavor. For the manufacture of beverages it is not so Wel I fitted lima use it removes. a lung with other impurities, a large proportion of the volatile oils which give them their peculiar flavor. For the principles involved in the process see l)fsrtL LATIoN Ev.seoit.trioN; Ptatirvimt TILE INSTILLED Smarr. if alcohol and water were the only substances that pass over in distillation, all spirits, from whatever source, svould be the same. But, except to it partial extent in the Coffey still, this is not the it se. Brandy, 111111, 111111 owe their dis thief ive flavors to essential oils derived from the grapy, limn sugar. or from grain. Other impuri ties also pass over which are unplua sant and unwhol•sione. The mellowing effeet of age upon spirits is said to he to the evaporation or simultaneous combustion of these oils. Newly distilled spirits are in general liery and un•hole some. The process of removing the impurities from the spirit, by fractional or repealed dis tillation• is known as rectifying the spirit. The spirit that is first condell,01, in rectifying, is crude and milky. Next comes the clear alcohol, is eaught qeparately. I.ast of all etanes a weak spirit ealled faintR, which is returned to the still. There are certain impurities which cannot be removed by distillation. fusel oil is one of these persistent impurit ie-t. Several chemical methods have he•n proposed for its . hut the MO 11(111 11,11,111y is to filter the alcohol, diluted suith equal parts of water, through wood charcoal. A proeess which has been used experimentally consists in mixing the diluted spirit with petroleum and thor oughly agitating the mixture. The iletroleutu has the power of withdrawing the fusel oil from the mixture. Absolute or anhydrous alcohol cannot be obtained by distillation. (See ..11.conoL.) Rectified spirit of wine. the name given to the most concentrated form of alcohol producible by distillation, contains 25 per cent. of water. The British Pharmacopeia describes rectified spirit as containing 84 per cent. by weight of real alcohol, and having a specific gravity of 0.520. United States Pharmacopeia defines alcohol as a spirit containing 91 per cent. of real alcohol. with a specific gravity of 0.83 to 0.:44. Proof spirit is a term applied to alcohol which e0Dionthi to the standard of purity laid down by English law for excise purposes. The specific gravity of proof spirit is 0.9180, and it contains about equal parts of water and alcohol. Alcohol is consider ably lighter than water (as 793 to 10001, and thus the lighter the liquid, the purer it is.
BEvErt.tc.Es MAN: FROM RECTIFIED SPIRIT. Whisky. brandy, and rum are distilled liquors used directly as beverages. But much of the dis tilled liquor produced is in the form of silent spirit, and is used to fortify wines and to arrest fermentation in them at any desired stage, and in the manufacture of factitious beverages gen erally. There is a large class of alcoholic bever ages which are made by mixing with alcohol or brandy various aromatic substances. These dis tilled spirits are discussed under LIQUEURS.
Btuttomt.venv. Brannt, Practical Treatise on the Rate Materials and the Distillation and the Rectification of Alcohol, and the Preparation of Alcoholic Liquors, Liqueurs, Cor dials. and Bitters (Philadelphia. ISSG) ; Gaber, r praktisrhe Destillateur and .•piritnosen-Fa brikant (Vienna. 1901) : Handbuch der Spiritusfabrikation (Berlin, 1A991. of which there is a French translation by Bosker and Warnery. entitled, de It fabrication de l'alrohol (Lille, ISS9): Roux, La fabrication de ralrohol, in seven parts (Paris, ltig3-90). See