REPORT OP COMMITTEE ON PUBLICATION 



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TABLE 5. 

 Summary of Analyses 1913 and 1914 Wines. 



Volatile Acid Average-- 

 Average Sugar 



Average Alcohol 12.07 



Average Total Acid 



Average Extract 3.15 



Average Tannin 212 



Maximum .Volatile Acid 



Maximum Sugar 850 



Minimum Volatile Acid 

 Minimum Sugar 050 



Discussion of 1913 Wines. 



The year 1913 was marked by very hot weather during the fermenting 

 season. For this reason practically every fermentation rose to a high degree, 

 100 to 105 F. being very common temperatures in the fermenting vats. 

 This, of course, caused a great deal of "sticking" of fermentations and in 

 making conditions favorable for the growth of acid forming bacteria. Fer- 

 mentations that were made with pure yeast and SO 2 reached just as high 

 temperatures as did the "natural" fermentations. The important differences 

 between the two were, however, that the wines fermenting with pure yeast 

 after treatment of crushed grapes with sulfurous acid, did not "stick" with 

 unfermented sugar and did not increase in volatile acid, while the naturally 

 fermented wines "stuck" in many instances and still more commonly de- 

 veloped very high volatile acid. These facts are distinctly brought out in 

 the individual analyses of Tables 1 and 2 and in the averages of sugar and 

 volatile acid determinations in Table 5. 



The average volatile acid for the wines fermented with sulfurous acid 

 and pure yeast was .058 per cent; for the naturally fermented wines, .114 

 per cent. None of the wines in which SO 2 and pure yeast were used were 

 above the commercial limit of .120 per cent (for white wines) or .140 per cent 

 (for red wines). Forty-nine out of 108 samples of the naturally fermented 

 wines were above .120 per cent and 30 out of 108 were above .140 per cent. 

 That is to say, almost 30 per cent of the naturally fermented wines "spoiled" 

 as judged by present commercial standards. On the other hand, the wines 

 made by the improved methods were all well below the limits set for volatile 

 acid, the maximum being .118 per cent, and only four out of 68 were above' 

 .09 per cent volatile acid. The average (.058) was far below this figure. 



The unfermented sugar in the wines made by the two methods compare 

 in about the same way as do the volatile acid contents. The naturally fer- 

 mented wines were much higher, on the average, in unfermented sugar than 

 the wines from the same districts made by pure yeast and SO 2 . The average 

 of .55 per cent of the naturally fermented wines is considerably above the 

 safety limit of .25 per cent for dry wines; that of .148 per cent for the pure 



