ALCOHOL 



27 



before puniping the mash through the cool- 

 ers into the fermenting cisterns. 



The apparatus and mashing process de- 

 scribed are designed primarily for use in 

 corn distilleries, but they may be adapted 

 with but little change to use with pota- 

 toes as a raw material. (1) 



Fermentation 



In order to minimize the chances for 

 souring and spoiling, the saccharine so- 

 lution intended for fermentation is 

 pumped to the fermenting cisterns as soon 

 as possible after its preparation. Yeast 

 which in the meantime has been pre- 

 pared (2) separately in a small tub from 

 a mash containing malt and either rye 

 or potatoes, is added to it at once in a 

 proportion varying between five and ten 

 per cent. If necessary, water is added to 

 fill the cisterns to within a few inches of 

 the top, and the whole volume of liquid 

 is thoroughly plunged or mixed. At this 

 time the solution should contain between 

 17 and 22 per cent of solids, as shown by 

 a reading of 17 degrees to 22 degrees on 

 the Balling saecharometer, and its tem- 

 perature should be between 60 degrees 

 and 65 degrees Fahrenheit. 



Within a few hours gas bubbles will be- 

 gin to. break the surface of the fermenting 

 liquid, forming a constantly thickening 

 cap of foam, and the whole mass of beer 

 will rapidly come into vigorous motion. 

 At the same time its temperature will be- 

 gin to rise, and its specific gravity, as 

 indicated by the saecharometer, will fall. 

 According to the temperature, the kind of 

 material fermented, and the strength of 

 the yeast, fermentation will be complete 

 within from 4S to 96 hours, as will be 

 shown by the gravity and temperature 

 ceasing, respectively, to fall and to rise, by 

 the solution coming to rest and losing its 

 foamy cap. and by cessation of the escape 

 of gas bubbles. The fermented liquor, or 

 distiller's beer, is now said to be "dead" 

 or "ripe," and is ready for distillation. 



If the composition of the mash and the 

 degree of fermentation are satisfactory, 

 the beer should increase about 30 degrees 



(1) See Farmers' Bulletin 410. p. 11. 



(2) Detailed dirertinns for raaltini: veast are 

 given on p. 2."! of Farmers' Bulletin 410. 



Fahrenheit in temperature above the point 

 at which it was set, its gravity should 

 fall almost to degrees Balling, and it 

 should contain between six per cent and 

 ten per cent of alcohol. 



Distillation 



The separation of alcohol from the fer- 

 mented liquors in which it is formed is 

 made possible by the fact that its boiling 

 point, 173 degrees Fahrenheit, Is lower 

 than that of water by nearly 40 degrees 

 Fahrenheit. On this account a mixture 

 of alcohol and water boils at a lower tem- 

 perature than water alone, and the vapors 

 which first arise from such a boiling mix- 

 ture are richer in alcohol than the liquid 

 itself. Thus, a mixture of alcohol and 

 water which contains eight per cent by 

 weight of alcohol, will boil at about 200 

 degrees Fahrenheit, and will produce a 

 vapor which contains approximately 43 

 degrees of alcohol by weight. A liquor of 

 the latter composition will in its turn 

 boil at about 181 degrees Fahrenheit and 

 will form a vapor containing about 68 

 per cent of alcohol. When such mixtures 

 are distilled all of their alcohol, mingled 

 with more or less water, will pass over in- 

 to the distillate, while a considerable pro- 

 portion of the water still remains in the 

 kettle of the still. It is possible, there- 

 fore, even with stills of such simple type 

 as are outlined in Fig. 1 and Fig. 2, to 

 obtain ultimately a fairly strong alcohol 

 by repeated distillation of the successive 

 distillates. 



Such a still as is shown in Fig. 2 will 

 produce in two successive distillations 

 (Singling and doubling) from 100 volumes 

 of a beer containing approximately 10 per 

 cent of alcohol about 37 volumes of a dis- 

 tillate of 67 per cent strength together 

 with about 23 volumes of weak distillates 

 which can be saved for subsequent re- 

 distillation. It would be impossible, how- 

 ever, to make any quantity of a 90 per 

 cent distillate with such an apparatus ex- 

 cept by incurring an expense for fuel and 

 labor which would far exceed the highest 

 possible industrial value of the product. 

 Fortunately it is possible so to con- 

 struct a still that the requisite number 

 of redistillations take place simultaneous- 



