Distillation.—Great distilleries are usually mounted with two stills, a larger and a smaller. The former is the wash still, and serves to distil from the fermented worts a weak crude spirit called low-wines ; the latter is the low wine still, and rectifies by a second process the product of the first distillation. In these successive distillations a quantity of fetid oil, derived from the corn, comes over along with the fast and last portions received, and con stitutes by its combination what is styled the strong and weak faints. These milty faints are carefully separated from the limpid spirit, by turning them as they begin to flow from the still into distinct channels, which lead to separate receivers. From these receivers the various qualities of spirit, low wines, and faints are, for the purpose of redistillation, pumped up into charging backs, from which they are run in gnaged quantities into the low-wine and spirit stills.
The distilling apparatus, in one of the large establishments near London, is thus arranged. The wash is conveyed through pipes from the fermenting vessel to the wash-charger, which is a closed iron cistern, capable of containing 30,000 gallons. From this vessel the wash flows into the wash-still, a copper vessel hold ing 20,000 gallons ; it is heated by a fire be neath, and is terminated at the top by a cover, which gradually decreases in diameter, and at length joins the worm, in another vessel. The wash is made to boil : and as alcohol boils and passes off in. vapour at a temperature of 180° Fakir., while water requires a temperature of 212°, the heating is so managed as never to reach ; and the alcohol vapour passes off with only a small portion of water vapour: if the process were perfectly conducted, there would be no water pass off with the spirit; but in practice there always is a small quan tity, and to this extent the spirit is weakened by the mixture. The alcohol-vapour passes off into the worm, which is a copper tube curved spirally round the inside of a vessel thirty feet high, called the worm-tub: the tube is two feet in diameter at the upper part of the vessel, and diminishes down to two inches near the bottom. The worm-tub is filled with constantly flowing cold water, which keeps the copper worm at such a low tempe rature that the vapour in the worm is con densed into a liquid. This liquid, forming
the low-wines, flows out of the narrow end of the worm into the low-wines receiver, from which it again flows into the spirit-still. An other distillation occurs, and sometimes a third, until so much of the water is driven off as to leave the spirit of a proper strength. Standard or proof spirit' consists of one half absolute or pure alcohol and one half water : if a given bulk of distilled water weighs 13 ounces, an equal bulk of proof spirit will weigh exactly 12 ounces. This difference of specific gravity gives rise to the construction and use of the HYDROMETER. There are certain stages or degrees of strength, above' or below proof,' according to circumstances : thus, the strongest spirit produced by distillation is , above proof, spirit of wine is not less than above proof, raw spirits sold by the distiller to the rectifier are at 25° and 11° above proof, gin is about 17° below proof. The rectifying, or giving a modified strength and a peculiar flavour to spirit, is effected in totally distinct establishments from those in which the spirit is produced from grain. Scotch and Irish whiskey are distilled spirit without artificial flavour. English yin is flavoured with juniper berries, sugar, and other substances.
A largo revenue is derived from distilled spirits ; and the revenue officers exercise a most rigorous supervision over all the opera tions of a distillery.
The total number of proof gallons of spirits distilled and charged with excise duty, in 1849, was as follow : England .. 5,318,526 gallons Scotland .. 10,-144,709 „ Ireland .. 8,117,844 „ 23,881,079 gallons.
In looking at these numbers, we cannot fail to be struck with the circumstance that Ire land, with half the number of inhabitants, manufactures 50 per cent. more spirit than England : and (more striking still) that Scot land, with one-fifth of the population, manu factures twice as much spirit as England.
The Excise duty (7s.10d. per gallon in Eng land, 3s. 8d. in Scotland, and 2s. 8d. in Ire land) realised 4,847,2171. in 1840.
A few additional details respecting distilled spirits will be found under BRANDY, Rum, &c.