Dr. Oscar Loew 53 



on the bean and affects its flavour, the bean 

 being, as may be said, ' stewed in its own 

 juice.' ' 



According to the laws of osmosis some acetic 

 acid and some alcohol from the fermenting 

 liquor will doubtless enter through the testa 

 and come in contact with the cotyledons, which 

 thereby may be killed, if the temperature of 

 the fermenting mass has not already accom- 

 plished this. The reaction of the cotyledons 

 after drying the fermented beans is acid, but 

 whether this is wholly due to the entering 

 acetic acid may be doubtful, since the reaction 

 is weakly acid in the fresh state. A stronger 

 acid reaction is shown by the slime tissue. 



The expression " stewed in its own juice " 

 used by Chittenden can hardly be admitted, 

 since the juice of the pulp, after being entirely 

 decomposed by yeast and bacteria, is certainly 

 not the "own juice" of the cotyledons. Still, 

 that author attributes to it the generation of 

 the flavour. 



The opinion of Prof. Harrison (see p. 36) 

 that the decrease of tannin during the fermen- 

 tation process stands in relation to the develop- 

 ment of the aroma (see p. 37) is certainly far 

 from the mark, as tannin cannot produce 

 ethereal oils by any oxidation or fermenting 

 process. Only colour and taste stand in this 

 relation to the tannin content. 



Several experiments were made by the 

 writer with an aqueous solution of i to 4 per 



