SOFT RESINS IN SULPHURED AND UNSULPHURED HOPS. 



15 



Fig. 6.- 



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-lodin-value curves of the soft resins in sulphured and un- 

 sulphured hops in cold and in open storage. 



CHEMICAL VALUES OF THE SOFT RESINS. 



In order to make more apparent the correlation between the various 

 chemical values found in the soft resins from year to year, these values 

 have been brought 

 together and are rep- 

 resented graphically 

 in figures 7, 8, 9, 

 and 10. 



Figure 7 shows 

 the various values 

 as found in the sul- 

 phured hops in cold 

 storage. The acid 

 value, which in- 

 creased during the 

 first year of storage, 

 gradually decreased 

 during the second 

 and third years. The ester value, which increased very rapidly 

 during the first year of storage, diminished somewhat during the 

 next two years. Figure 7 shows also that although esterification 

 took place rapidly during the first year of storage it could not keep 



pace with the forma- 

 tion of free acids; 

 thus the latter in- 

 creased. During 

 the remainder of the 

 time the hops were 

 in storage esterifica- 

 tion continued, but 

 the quantity of free 

 acids formed was not 

 so great, with the re- 

 sult that there was 

 a decrease in free 

 acidity. 



The saponification 

 value gradually in- 

 creased throughout 

 the storage period. 

 The iodin value at 

 the end of the first year of storage was less than that of the original 

 sample, indicating that the formation of unsaturated compounds in 

 the soft resins had been retarded in the sample held in storage. The 

 iodin value increased during the second year, indicating a greater 

 production of unsaturated compounds in the soft resins. 



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w 







^ 



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Fig. 7. 



-Curves showing the correlation of chemical values of the 

 soft resins in sulphured hops in cold storage. 



