\i 11)11 ■^ IF w 1 \i'. 40<) 



(2) Wlifii the air had access thi<iu_^h ilie coUon-wodl phigs, the 

 Nolatile aciih'ty in tlie case of the same four yeasts was as 



li >11( i\\ > : 



tirst two yeasts the volatile acidity increased strongly- from the 

 23rd May to the 4th October, whereas in the case of the last twt> 

 there was a sli_2;ht decrease. The alcoholic fermentation was 

 much more vigorous where air i^ot access than where it was ex- 

 cluded. 



For every determination a dilTerent bottle was used, and in 

 every case the wine contained only 2 to 3 ^v. sugar per litre, 

 except in the case of Chardonnay 1 (with air excluded), where 

 the wine still contained 10 to 34 gr. sugar per litre. 



The following are .some of the autlKjr's conclusions : — 



( I ) After the fermentation l)y pure yeast with access to the 

 air on and in the lees a renewed growth of yeast takes 

 place. 



(2 ) In such cases up to al)out i .8 per mille volatile acid (as 

 acetic acidj can lie formed in the course of 4 to 3 

 months in wine kept in small \ essels at the temperature 

 (j'f the room. 



(3) A small amount of this volatile acid is formed duriaig the 



fermentation, l)Ut the ])ulk of it is subse(|uently formed. 



(4) As this formation of \olatile acid sul)se<|uent to the 



fermentation ■synchronises witli the new growth of 

 yeast on the lees, t]ii-> latti'r must be regarded as causintr 

 the great increase in tlie \-olatik' acidit\- of the wine. 



In 11J13 \'on der I leide and Scliwenk (14) published the re- 

 sults of their work on the \'olatile acidity formed l)y 3'east din'in^'- 

 the re fermentation of wine. They tested the effect of the num- 

 bers of yeast cells brougln into the wine, as well as that of the 

 alcohol and sugar i^resent in the wine at the time of inoculation. 



Three series of experiments were conducted where, respec- 

 tively 0.672. 25.12. and 489,600 million yeast cells were intro- 

 duced into I litre of the experimental sterile li(|uid. Under 

 each yeast concentration there were four groui)s of three exjjeri- 

 ments. A ])ure wine was evaporated //; vacuo to one-tenth its 

 original \olume. wlien it was l)roug]u l)ack to its original volume 

 by adding water and pure alcohol . Tlie latter was added in four 

 different amount> to give four different li(|uids for the experi- 

 meiUs of groups i, 2, 3. 4, which liad to contain respectivelv 

 3. 4, 3 and () gr. alcohol ])er roo c.c. In the case of each group 

 three dilYerent amounts of sugar were added to test its influence, 



