CAPE WINE-LEVURES. 241 



decomposed the remaining sugar. The wine of B. was dry on 

 the 3rd March. This was to be expected, since the levures here 

 got much more air than in case of A. 



Both wines were analysed on the 3rd .May, 191 1, with the 

 following results : 



Alcohol: A 15.23 volume per cent.; B. 14.71 volume per cent. 

 Total Acidity : A. 5.8 per mille as Tart, acid ; B. 5 per mille as 



Tart. acid. 

 Volatile Acidity: A. 0.58 per mille as Acetic acid; B. 0.61 per 



mille as Acetic acid. 

 The main differences between the closed and the open fer- 

 mentation may briefly he summarised as follows: 



( 1 1 The wine sooner ferments dry with an open fermenta- 

 tion (B) than with a closed fermentation (A). 



( 2) The alcohol lost by evaporation during an open fer- 

 mentation is so considerable that the wine B. has 0.52 volume 

 per cent, alcohol less than wine A., although the two musts had 

 originally practically the same amount of sugar. 



13) In a fermentation with the dops (open) more fixed 

 acid is lost to the wine than in the other case. 



1 4 1 The volatile acid in B. is slightly higher than in A. 

 (closed), although the maximum temperature was higher in A. 

 than in B. 



( 5 ) But the main difference is that the wine that was 

 subjected to a closed fermentation without the dops, is a line, 

 clean, pleasant wine, whereas the other is a coarse, ordinary wine, 

 far inferior to the first. The grapes were of the same quality 

 and from the same plot of vines in both cases. 



(6) It will be noticed that the wine A. has over 15 volume 

 per cent, alcohol. 



5. Greengrape (Sauternes). Vintage 191 1. 



By removing half of the leaves of the vines when the grapes 

 were well ripe, and leaving them exposed to the sun on the vines 

 for about a fortnight, the sugar went up to 29. 5 ° Balling. 



The grapes were crushed and the juice pressed out on 17th 

 February, 191 1. To just under one half-aum must was added 

 100 grs. Potassium metabisulphite (i.e., 700 mg. per litre must 

 sulphur dioxide). Since there was no fermentation noticeable 

 on the 25th February, 191 1. the must was exposed to the air in 

 an open tub for about eight hours and then put back into the 

 ca-k. Thereupon a fermentation slowly set in. On the 26th 

 March, i.e., five weeks after crushing, the wine was quite bright 

 and had a nice bouquet. 



