WHISKEY. 171 



403. During the fermentation of the wort, as in all 

 similar operations, a quantity of a peculiar volatile 

 oil is produced, some of which passes over with the 

 spirit when it is distilled ; that which is obtained 

 towards the end of the distillation is generally most 

 contaminated with this oil, and is termed faints. 

 The wash usually yields rather more than one-tenth 

 of its volume of pure alcohol, or one-fifth of strong 

 spirit, half of which is pure alcohol ; — for the strong- 

 est spirit which can be thus obtained, always con- 

 tains a considerable quantity of water (368). 



404. As there is an excise duty on the manufac- 

 ture of spirit, it is necessary to estimate the strength 

 and quantity of spirit which the distiller obtains. In 

 doing this the spirit is stated to be over or under 

 proof. Proof spirit consists of equal parts of water 

 and alcohol. It was formerly the custom to pour a 

 small quantity of the spirit to be tested, over gun- 

 powder, and then set fire to it ; if the spirit was 

 strong, the gunpowder fired, and then the spirit was 

 called proof spirit ; but if it contained too much 

 water, the gunpowder was not fired. 



405. This method of testing the strength of spirit 

 is highly inaccurate. As alcohol is much lighter 

 than water, the strength of spirit is easily ascertained 

 by weighing a portion of it in a bottle, the capacity 

 of which is known ; this gives its specific gravity, or 

 weight, compared with an equal bulk of water, and 

 from that it is easy to calculate its strength. 



406. The flavor of the grain spirit, or whiskey, 

 thus obtained, depends a good deal on the ferment 



