36 ORGANIC AGRICULTURAL CHEMISTRY 



again through a rectifying or column still. This is a tall still 

 containing many condensing plates so that the alcohol is still 

 more perfectly fractionated. By this second distillation the 

 purest and strongest alcohol of commerce is obtained. It is 

 about 95 per cent, by weight, and is commercially known as 

 Cologne spirits. 



Absolute AlcohoL — For the preparation of absolute or loo 

 per cent alcohol the 95 per cent product is placed over quick- 

 lime, CaO, and after standing to allow the lime to remove all 

 water the whole mass is heated and alcohol passes over as 100 

 per cent. Anhydrous copper sulphate may also be used as a 

 dehydrating agent, but this is common only in laboratories and 

 not in commercial practice. 



Absolute alcohol, because of its affinity for water, acts as a 

 dehydrating agent, and is used to remove the last traces of water 

 from some substances, especially animal and plant tissues. It 

 can be kept only in bottles well stoppered. 



Alcoholic Beverages. — The use of alcoholic beverages is an 

 ancient and very general custom. The natural alcoholic bever- 

 ages are the weaker in alcoholic content and are simply the 

 undistilled fermentation liquids. They are wine, beer, ale, 

 stout and others similar in character, but with different names. 

 Wine is the simple fermented grape juice and contains 7 per 

 cent to 20 per cent alcohol. Those above 14 per cent are 

 termed fortified wines because they have alcohol added to them. 

 Beer, ale and stout are fermented liquors obtained by filtering or 

 decanting off the fermented liquid made from barley in the 

 general manner described in the manufacture of alcohol. These 

 are still lower in alcohol content than wine, being between 2 

 per cent in pale beers to 5 or 6 per cent in ales and porters. The 

 characteristic taste or flavor of wines and the names given to 

 them depend upon the variety of grape used, the locality where 

 the wine is made, or the particular processes involved in its 

 manufacture. The same general facts determine the quality 

 and name of the beers and ales. 



When a fermented mash prepared from grain or from fruits 



