DISTILLATION 53 



Distillation of Spirits. In the manufacture of ardent spirits, the alcoholic liquor 

 obtained by fermentation of a saccharine solution is submitted to distillation ; the 

 alcohol being more volatile than the water passes over first, but invariably a consider- 

 able proportion of water is evaporated and condensed with the alcohol. To separate 

 this water to the required extent it is necessary either to submit the product to redis- 

 tillation, or to contrive an apparatus such that the product of this first distillation is 

 returned to the still until a spirit of the required strength is obtained. 



One of the earliest and simplest contrivances for effecting the latter object is the 

 still invented by Dorn, which is employed up to the present time in Germany (Jiff. 

 623). A is the still, heated by the direct action of the fire ; B the head, from which 



623 



r conveys vapour to a small refrigerator, for the purpose of testing the strength of the 

 distillate ; E is an ordinary condenser, containing worm, &c. The intermediate copper 

 vessel answers two purposes : the upper part c forming a heater for the wash, while 

 the lower compartment D acts as a rectifier. The heater c, when filled up to the level 

 of the cock m, contains the exact measure of wash for charging the still ; the contents 

 can be constantly agitated by the rouser z. The still and heater being both charged, 

 the vapour will at first be completely condensed in passing through the worm g, and 

 flowing into D will close the aperture. When the cpntents of c become so hot that no 

 more condensation occurs, the vapour will escape by bubbling through the liquid in D, 

 which latter rapidly becomes heated to the boiling point, and evolves vapours richer 

 in alcohol, which in their turn are condensed in B. 



In this manner, by one operation, spirit containing about 60 per cent, of alcohol is 

 obtained. 



Of the recent improvements on Dorn's still two only need be described : Coffey's, 

 which has in a great measure replaced all others in this country ; and Derosne's, which 

 is extensively employed in France. 



Coffees Still far surpasses any of those before described. It was patented in 1832, 

 and has proved most valuable to the distiller, since it yields the strongest spirit that 

 can be obtained on the large scale. 



Its objects are twofold : 1st, to economise the heat, as much as possible, by ex- 

 posing the liquid to a very extended heated surface ; 2nd, to cause the evaporation of 

 the alcohol from the wash by passing a current of steam through it. 



The wash is pumped from the ' wash charger ' into the worm tube, which passes 

 from top to bottom of the rectifier. In circulating through this tube its temperature 

 is raised to a certain extent. Arrived at the last convolution of the tube in the rectifier 

 the wash passes by the tube M (fig. 624) in at the top of the ' analyser.' It falls and 

 collects upon the top shelf until this overflows, whence it falls on to the second shelf, 

 and so on to the bottom. All the while steam is passed up from the steam boiler 

 through fine holes in the shelves, and through valves opening upwards. As the wash 

 gradually descends in the analyser it becomes rapidly weaker, partly from conden- 

 sation of the steam which is passed into it, and partly from loss of alcohol, either 

 evaporated or expelled by the steam ; till, when it arrives at the bottom, it has parted 

 with the last traces of spirit. At the same time the vapour, as it rises through each 

 shelf of the analyser, becomes continuously richer in alcohol, and contains less and 

 less water in consequence of its condensation ; it then passes from the top of the 



