10.1 



CHAPTER III. 



or THE SACCHARINE FRUITS, JUICES, AND INFUSIONS USED IN THE 

 PREPARATION OF FERMENTED AND SPIRITUOUS LIQUORS. 



The juice ol* all the sweet fruits when expressed and left to 

 itself under the influence of a suitable temperature, presents the re- 

 markable phenomenon of fermentation, in the course of which the 

 sugar disappears conipleiely, and is replaced by alcohol, the change 

 from first to last being accompanied by the disengagement of car- 

 bonic acid gas. 



Sugar alone does not suffice to cause the vegetable juices, which 

 contain it, to ferment : for example, a solution of pure sugar in di.s- 

 tilled water will remain for a very great length of time without suf- 

 fering the least change ; exposed to the open air it would evaporate, 

 and the saccharine matter would be found in the same' state as it 

 was before solution If, however, a small quantity of that azotized 

 principle which we have called albumen, gluten, &;c., be introduced 

 into the solution, fermentation will speedily be set up, and will run 

 through its usual course; it would, therefore, appear to be upon this 

 principle that the commencement and continuance of fermentation 

 depends. Fermentation is not set up immediately in the juice of 

 fruits ; a certain time longer or shorter always elapses before it is 

 manifested ; the reason of this is, that the albumen or gluten which 

 always enters into the constitution of these juices, must itself have 

 undergone a certain change in order to act as a ferment. The proof 

 of this is comprised in the fact that all vinous liquors contain a very 

 small but constant quantity of carbonate of ammonia, as was shown 

 by M. Doebereiner. These azotized principles, which in the fresh 

 state remain without action upon sweet juices, act immediately as 

 powerful ferments when they are employed after having been ex- 

 posed for some days to the contact of air and moisture ; after, in a 

 word, they have themselves begun to suff'er change. The quantity 

 of ferment used up or consumed in exciting and maintaining the fer- 

 mentation of saccharine juices is so small, that we are led to believe 

 that it really acts by its presence or contact alone. This view ap- 

 pears the more likely, when we know that, after having added an 

 azotized substance to induce fermentation rapidly in a liquid which, 

 besidee sugar, contains albumen, we find from six to eight times the 

 quantity of ferment after the phenomena have ceased, which had 

 been added in the first instance ; that is to say, we find the whole, 

 or almost the whole, of the original ferment, and, in addition, that 

 which has been produced by the azotized principles pre-existing in 

 the matter subjected to fermentation ; this fact is seen every day in 

 the process of making beer. 



The ferment or yeast thus produced is but little soluble in water, 

 and in composition bears a remarkable aftinitv to the azotized mat- 



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