A VINOUS SMELL. 309, 



On this account every acid produced from wine, 

 either during fermentation or at a later period in any 

 other manner, may, by separation of the tartaric acid, 

 originate the ether of the new acid ; and the tartaric 

 acid thus thrown off may serve for the reproduction 

 of etherised tartaric acid, and thus the whole process 

 begins again. Just as the decomposition of one sul- 

 phovinate may give rise to another sulphovinate, so 

 may the ether, freed from tartaric acid, combine with 

 another acid. 



During the fermentation of grape-juice, a very rapid 

 formation of etherised tartaric acid may be expected. 

 This occurs during the first days of fermentation, 

 before the liquor has acquired any vinous odour. 



A second period now begins, which we have dis- 

 tinguished by the name of after-fermentation (p. 91). 

 During this period the peculiar vinous smell of the 

 liquid is developed, and as this must be attributed to 

 oananthic ether, we have now to seek after the origin 

 of cenanthic acid. If the oenanthic acid exist in the 

 wine (and it is partly contained in it in a free state, 

 for it can be so obtained by distilling the sediment) 

 it will decompose the scentless etherised tartaric acid, 

 and give rise to oenanthic ether, that is, to the liquid 

 which imparts vinous odour to all wines. 



The formation of osnanthic ether in wine is pre- 

 ceded by the production of many fatty acids, most of 

 which are formed in the course of time, and impart a 

 peculiar kind of fragrance to old wines. 



