The Kinds of Work That Are Done by riants 



99 



we give the name beer, "lager beer," to the hquid resuUing. 

 And innumerable other sweet juices and saps are fermentable, 

 with resulting formation of alcoholic beverages, which are so 

 many and diverse in kind that most nations have each some 

 favorite one of its own, the differences between them being due 

 in the main to various flavoring materials originally present with 

 the sugar. None of these fermented liquids, however, are ever 

 stronger in alcohol than the ten per cent, or thereabouts, which 

 the Yeast can yield before it is killed. The stronger liquors are 

 obtained by an additional and very different kind of operation, de- 

 pending on the fact that alcohol boils at a much lower temperature 

 than water (78°C, or 172°F as compared with 100°C or 212°F). 

 For this reason a fermented liquid, if heated above 78° but 

 under 100°, gives off its alcohol (though also with some water) 

 as vapor, which can be conducted away, cooled and collected 

 as a strongly alcoholic hquid. The process is called distillation, 

 and in this way are made the stronger alcoholic drinks, — brandy, 

 whisky, rum, gin, and all the remainder of this precious rogue's 

 gallery, — their peculiar flavors and colors being due to particular 

 substances, sometimes naturally present and sometimes purj^osel}^ 

 added, in the juices from which the alcohol is fermented. It is by 

 repeated distillation of the fermented juice of germinating corn 

 that the strong alcohol of commerce is made, and this when mixed 

 with a little of the poisonous wood alcohol to make it undrinkable 

 becomes the ''denatured alcohol" of the household and the chaf- 

 ing dish. 



We turn now to the chemistry of fermentation, which is simple. 

 It is grape sugar which is fermented, for other sugars or starches 

 are first changed to that form or its equivalent. Therefore we 

 have this expression. 



In fermentation CgHiaOe forms COg and C2H6O 



grape sugar carbon dioxide alcohol 



This statement can be given an exact chemical form in this 

 way,— ^ 



