Page:The American Cyclopædia (1879) Volume VI.djvu/150

DISTILLATION at a temperature of about 150 F. The mash- ing is continued one hour and a half, during which time 500 gallons more of water at 190 to 205 are introduced at intervals, to keep up the heat. The whole is then allowed to infuse two hours, during which time the grain sub- sides, and the liquid above it is a sacclrarine turbid fluid, called wort, which also still con- tains some starch and dextrine ; but these by the action of the diastase are gradually con- verted into grape sugar. At the end of the two hours' infusion the greater part (usually about two thirds) of the wort is drawn off, and 600 gallons of water at 190 is added, and the infusion is renewed and continued another hour and a half. After the wort is again drawn off, a third infusion succeeds, with 800 gallons of boiling water. This being well stirred for 20 minutes, and then left about half an hour, the saccharine matters are found to be extracted. The weak wort is then drawn off and boiled down to the required strength, or it is added to the first and second worts, or is kept to be used instead of pure water for the first infusion of the next mashing. Strong worts are not desirable, the fermentation being more complete and the yield of spirits greater when they are of moderate specific gravity. By the old excise laws of Great Britain they were required to be of a certain high degree of strength, but in Scotland and Ireland they are now allowed to range from 1030 to 1080 sp. gr., water being 1000. The next process is that of cooling the worts, and in consequence of the tendency of those produced from raw grain to become acid, this must be rapidly ac- complished. In some distilleries the wort is run into large shallow coolers in airy situations in the upper part of the building. In others the cooling is done by a more compact form of refrigerator, a description of which is given in the article BREWING. The temperature is usually reduced to between 70 and 75, when the worts are transferred to the fer- menting tuns, and yeast is added in the proportion of about one gallon to 100 gallons of wort. The object of fermentation is to convert all the saccharine matter, if possi- ble, into alcohol and carbonic acid ; but the presence of the alcohol as it is formed impedes the progress of this change, and a quantity often amounting to one fifth of the whole sac- (harine matter escapes decomposition. By the invention of Mr. Sheridan in fermenting the wash in close tuns, and causing the alcohol to evaporate by using a powerful air pump, the whole saccharine matter was converted into alcohol; but the excise restrictions prevented the adoption of the improvement. As the fer- mentation proceeds the liquor attains a less specific gravity, and when successfully con- ducted its density gets to be the same as that of water. If it is pushed too far, or goes on sluL'trishly or at too high a temperature, loss will result by a portion of the alcohol passing to acetic acid, the presence of which is indi- cated by increased specific gravity, as well as by its peculiar odor and taste. The process of distillation, which, by distinguishing the prep- aration of ardent spirits from that of fer- mented liquors, gives its name to the whole operation, now succeeds the fermentation. It is conducted in stills of various sizes and forms, some of which have a capacity equal to distilling from 2,000 to 3,000 gallons of wash per hour. The origin of the first still which abolished to a great extent the use of the worm and substituted condensing vessels, which principle has been retained with modi- fications in nearly all subsequent inventions of the kind, is due to a Frenchman named Edou- ard Adam, who is said to have been a distil- ler, unacquainted with anything more than the routine of his trade. In 1801 he witnessed some experiments with a Woulfe apparatus at a chemical lecture in Montpellier, and was so impressed with its advantages that he soon after constructed a still upon the same prin- FIG. 8. fidouard Adam's Still. ciple. This succeeded so well that the whole process of distillation was soon completely changed. The uses of Woulfe's apparatus are described in the article on GAS, and by re- ferring to that it will be seen that Adam's still was one of the happiest adaptations of a labo- ratory appliance to a manufacturing purpose. The modification of it as made by M. Adam is represented in fig. 3. A number of egg-shaped copper vessels, corresponding to the Woulfe bottles, are placed in convenient situations near each other, the terminal ones being con- nected on the one hand with the retort or boil- er containing the fermented liquor or wine, and on the other with a worm which is immersed in a cooler. The neck of the retort passes into the first egg-shaped vessel, dipping below the surface of the liquor. It is perforated at its termination with minute holes through which vapor passes. A pipe from the first egg leads to the second, also dipping beneath the sur- face of the liquor, and so on, from one to the next, whatever the number may be. From the last egg a tube enters the globe B before