2 4° CAPE WINE-LEVURES. 



FERMENTATION WAS STILL KEPT UP BY THE PURE LEVURE GB X 

 AT 41° C. ' " v5 ' 



( 2 ) It succeeded under such extreme difficulties, in ferment- 

 ing the mine dry, and forming 15.19 volume per cent, alcohol, 

 which means 10 volume per cent, alcohol for about 163 grs. sugar 

 per litre must, or 96% of the total sugar decomposed to form 

 alcohol. This, of course, is a very high yield of alcohol. 



(3) The high volatile acidity is due 'to the excessively high 

 temperature. In the hogshead where the maximum temperature 

 was two degrees lower than in the stukvat, the volatile acidity 

 of the wine was 0.18% lower than that of the wine in the stukvat. 

 That this volatile acid is principally formed by the pure levures 

 themselves, and not by acetic bacteria, is evident from the fact 

 that the wine remained sound and showed no bacteria to speak 

 of. Before it was fortified, expert tasters declared it to be a 

 very fine, full-bodied, perfectly sound ivine. They thought it 

 could hardly have more than 0.5% volatile acid. A spontaneous 

 vinous fermentation at 41° C. will in almost every case get stuck, 

 and give way to a mannitic fermentation, the result being a 

 sweetish-sour wine, that ends its life in a spirit-still. Such 

 wines have repeatedly been sent in to me for examination. The 

 cause of the disease was in every case a spontaneous vinous 

 fermentation at too high (above 37 C.) a temperature. 



The above experience shows that it is possible to make :« 

 perfectly sound, heavy, dry wine even at very high temperatures 

 by using a good pure levure, such as GB3. 



(4) That the amount of glycerine formed is fairly high. 



4. Greengrape fermented : 



A. Without husks. 



B. With husks. 

 Composition of must : 



A. Sugar = 26.4° Balling; total acidity = 6.19 per mille a-» 



Tartaric acid. 



B. Sugar = 26.3 Balling; total acidity = 6.24 per mille as 



Tartaric acid. 



A. was fermented all along in a stukvat (closed fermentation) ; 



B. was fermented in a cement tank (open) for 48 hours, and 

 was then transferred to a stukvat. 



A. B. 



Fermentation-temperature minimum 24.5 ° C. 25 ° C. 



Fermentation-temperature maximum 36 C. 35 ° C. 



Both were started with a pure culture of GB3 as soon as the 

 grapes had been crushed. They were both pressed on the 13th 

 February. 



Since the wine of A. was still somewhat sweetish on 14th 

 March, 191 1, it was again inoculated with GB3 on this date, and 

 racked over. After a few days a fermentation had set in and 



