Page:The American Cyclopædia (1879) Volume VI.djvu/152

144 DISTILLATION the upper boiler, and consequently lowering its boiling point. The vapors ascend into the rectificators B and C. The lower rectificator, B, contains a number of shallow pans perforated with holes, and a number of spherical disks, also perforated with holes, placed above them, in pairs, the convexity of each disk being upward, and receiving the drip of the shallow pan next above it. This drip is produced by warmed wine which flows from the wine heater through the pipe L. By these means the vapors ascending from the upper boiler have their more watery portions condensed, while the alcoholic vapor continues to ascend. The dripping wine also has a portion of its alcohol expelled in the form of vapor, which ascends with the vapor coming from below into the upper rectificator through the orifice O in its bottom. This upper rectificator com- municates through the tube M with a worm (which is the dephlegmator) in the wine warmer D, the worm ending in the tube w, which again terminates in the worm contained in the condenser F through a cylindrical con- nection in its upper part. The worm in F ter- minates in a small vessel, N", which is furnished with an alcoholometer. The alcohol in N flows from its upper part into the cistern H. The upper rectificator C is divided into a number of compartments by as many horizontal parti- tions, each disk having an orifice in its centre, like the orifice at 0. To each of these orifices on the upper side of the partition is adjusted a short open vertical tube. A short distance above each tube is placed an inverted pan, having its edges descending about three fourths of an inch below the level of the upper orifice of the tube. As the vapors ascend from the lower rectificator into the upper one, a por- tion of them condense and collect upon the bottom of the compartments until they rise slightly above the edges of the inverted pans and nearly to the upper orifices of the tubes. When this takes place the vapor can only pass upward "by forcing its way under the edges of the pans, by which means the more watery portion is still further condensed, the more alcoholic vapor, having a higher tension, retain- ing its gaseous form, and passing on through the tube M into the dephlegmatory worm in the wine heater, there to be partially condensed ; which process heats the wine surrounding the worm. A phlegma collects in the lower con- volutions, which may be drawn off by means of the pipes p, p, p, and transferred at plea- sure either into the tube ra or into the upper rectificator. The purer alcoholic vapors which arise pass through the dephlegmator into the condensing worm in the condenser F, whence they flow in liquid form into the vessel N, and thence into the cistern II. The strength of the alcohol produced by this still depends upon the number of windings of the dephlegmator, and the number of partitions in the upper rec- tificator. Derosne's still requires but little fuel, distils rapidly, and yields a good spirit, which may be varied in strength at pleasure ; but it is rather complicated, and may with ad- vantage, especially when spirits of only one strength are required, be replaced by a simpli- fication of it, devised by Laugier. The products of the distilleries of different localities are dis- tinguished by peculiar flavors which give them a reputation ; but they are not always, espe- cially when the liquor is made from cereals, derived from the original qualities of the ma- terials, but often from the fuel used in drying the malt. Much of the Scotch and Irish whis- key possesses the peculiar flavor of peat smoke. Brandies manufactured from wines are made to retain their peculiar flavors by conducting the distillation at a temperature sufficient to carry over the volatile oils and ethers, and also enough water to reduce the strength consider- ably below that of ardent spirits produced in Great Britain ; but they may be given strength by the addition of pure spirit. Common alcohol is the hydrated oxide of ethyle, or ethy lie alcohol, CJIioO + HsO^CJIeO. In the process of vi- nous fermentation there are formed, under con- ditions which are not yet clearly understood, other homologous alcohols, such as propylic, butylic, and amylic alcohols, in greater or lesser quantities. They have a higher boiling point than ethylic alcohol, and therefore do not usually appear in the first products of distilla- tion ; but in the latter stages of the operation, when the heat is raised, they pass over into the worms or condensers. These alcohols, mixed with some ethylic and small quantities of va- rious ethers and volatile fatty acids, such as capric, caprylic, and formic, constitute an oily substance which passes under the general name of fusel oil. That of potato spirit consists al- most wholly of amylic, combined with a small quantity of ethylic alcohol. This fusel oil im- parts a very disagreeable taste to spirits, and to get rid of it is often a matter of importance. The process is called rectification, and may be conducted with or without redistillation. Its complete removal by distillation, even with the use of alkalies and other substances, is some- what difficult and expensive, notwithstanding that the boiling point of absolute ethylic alco- hol, 173, is much lower than that of the others, amylic alcohol boiling at 270. It is found, however, that an elimination can be satisfac- torily effected by filtration through granulated charcoal which has been recently heated. About three fifths of the products of distillation in the United States are what are termed high- wines or whiskey, containing about 75 per cent, of alcohol. This, as it comes from the still, contains a good deal of fusel oil. Some of it is made into cheap whiskey, and the remainder is rectified and redistilled into French spirit. When the percentage of alcohol is high it forms Cologne spirit. About one fifth of the products of distillation is alcohol, which is all used for manufacturing and mechanical pur- poses, about 6,000 barrels being exported from the United States monthly. The remaining