414 ACIDITY OF \VIXI>. 



D. fermentations ai 40 C. — The bottles were inoculated <»n 

 13th June, 1917, and the fermentation, which was slow and 

 feeble, was over on 23rd June. 1917, when the analyses were 

 made. Only one bottle was taken for each concentration of 

 the must, and the loss in weight of the bottles was not recorded. 



Table I'll. 



P Q R 



Alcohol in volume per cent 3.33 5.55 4.88 



Volatile acid as gr. acetic acid per litre . . 0.70 0.84 0.90 

 Total acid as gr. tartaric acid per litre . . 3.4 ^>.4 7-2 



'J^ie wines were still very sweet when analyzed. 



III. Experiment io determine at which Stage of the J'crmenfa- 

 thn the P''olatile Acid is Formed. 



A bottle containing 400 c.c. of must at 22.5'' ©ailing wa> 

 inoculated with a pure culture of HaB.. and kept in the thermo- 

 stat at 40° C. The (fermentation was feeble. The volatile acidity 

 three days after the fermentation conmienced was 0.94 per cent., 

 the next day it was still 0.94 per cent., and 10 days after the fer- 

 mentation had commenced it was o.(/) j^er cent. This shows that 

 the bulk of the vola'tile acid formed by the yeast was formed 

 during the early and stormy v)art of the fermentation. 



Discussion of Results. 



In order to be able better to compare the amounts of vola- 

 tile acid formed in the different experiments, I shall now re- 

 group the results in one table, giving the actual amounts of 

 volatile acid formed, as well as the amount of volatile acid 

 formed per 100 volume per cent, alcohol formed at the same time. 

 In the case of the duplicates in Tables I\' to \'I the mean 

 values are given. 



