SOFT RESINS IN SULPHURED AND UNSULPHURED HOPS. 19 



The percentage of soft resins in all the samples decreased with each 

 year of storage, becoming very pronounced in the third year. The 

 percentage of hard resins in all the samples increased with each year 

 of storage, approaching a uniform figure at the close of the third year. 

 Both sulphuring and cold storage retarded the decrease in the per- 

 centage of soft resins and increased the percentage of hard resins. A 

 combination of the two factors was more effective in retarding these 

 changes than either factor alone. 



The percentage of total resins in all the samples varied from year to 

 year, and in the third year it became materially less than that of the 

 original sample. The low total is probably due to the formation of 

 products insoluble in the solvents used. 



The color, odor, and taste of the soft resins are of very little value 

 in determining quality and are not indicative of any changes that may 

 have taken place therein. 



The acid value in general decreased in the sulphured hops in cold 

 and in open storage and increased in the unsulphured hops in cold 

 and in open storage. Sulphuring apparently retards the formation 

 of free acids, and a combination of sulphuring and cold storage is 

 most effective in retarding changes in free acidity. 



The ester value in general increased in all the samples of hops. 

 Sulphuring apparently favors the formation of esters, and this factor 

 in combination with open storage appears to be the least effective in 

 retarding the formation of esters. Nonsulphuring and open storage 

 appear to be the most effective in retarding the formation of esters. 



The saponification value in general increased in all the samples of 

 hops. The unsulphured hops showed the least change, and of these 

 the ones held in open storage were the least affected. 



The iodin value hi general increased in all the samples. It was 

 most pronounced hi the second year of storage and in the third year 

 was uniform in all the samples. Sulphuring hi combination with 

 open storage appears to cause a uniform rate of increase in the iodin 

 value from year to year. The sulphured hops in open storage showed 

 the least variation in changes in the chemical values of the soft resins. 



During the period of storage, at least some of the components of 

 the soft resins underwent rearrangement. This rearrangement was 

 most marked during the first year, after which it decreased to such 

 an extent that thereafter comparable values for the chemical constants 

 were readily obtained. 



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