REPORT OF COMMITTEE ON PUBLICATION 263 



and well marked. The averages of .098 volatile acid for the naturally fer- 

 mented wines and .049 for those made with SO 2 and pure yeast prove this 

 statement. 



Summary. 



1. The wines made in 1913 with SO 2 and pure yeast were very much 

 lower in volatile acid and unfermented sugar and contained a much smaller 

 number of "tourne" bacteria than wines from the same district made in the 

 usual way by natural fermentation. The 1913 season was very warm; there- 

 fore, the results demonstrate the efficacy of pure yeast and SO 2 in producing 

 sound wines under adverse high temperature conditions. 



2. The 1914 wines showed less difference in quality and composition, but 

 what difference there was lay definitely in favor of the wines made with SO 2 

 and pure yeast. The 1914 season was very cool and most favorable for sound 

 natural fermentations. The fact that the wines made by the improved 

 methods were superior to the naturally fermented wines demonstrates that 

 the use of SO 2 and pure yeast gives better results (on the average) than 

 natural fermentations even under favorable conditions of temperature. 



Conclusions. 



1. The quality and soundness of wines made in the ordinary commercial 

 cellars can be raised very materially by the use of SO 2 and pure yeast. 



2. Special technical knowledge is not necessary for their use and they 

 can be applied by the average wine maker. 



A SIMPLE AND RAPID METHOD FOR THE ESTIMATION 

 OF VOLATILE ACID IN WINE. 



By PROF. W. V. CRUESS, 

 University of California, Berkeley, Cal., 



and 



R. W. BETTOLJ, 

 San Francisco, Cal. 



Most of the methods for volatile acid estimation in wine require rather 

 complicated apparatus for the distillation of the volatile acid so that the ordi- 

 nary wine maker or wine buyer does not feel inclined to master the intricacies 

 of the process in order that he might use it himself. It is the most impor- 

 tant chemical determination to be made in judging the soundness of wine 

 and is a great aid in deciding how to handle certain wines during aging. 

 Therefore, any simplification of present methods of making this test would 

 be very desirable. 



In the official method a 50 c. c. sample of wine is distilled in a current 

 of steam till 250 c. c. of distillate is collected. This distillate is titrated 



