16 



BULLETIN 282^ L T . S. DEPARTMENT OF AGRICULTURE. 



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Pkj. 8. — Curves showing the correlation of chemical values of the soft 

 resins in sulphured hops in open storage. 



Figure 8 shows the various values as found in the sulphured hops 

 in open storage. The acid value, which remained almost constant 



during the first year 

 of storage, gradually 

 diminished during 

 the next two years. 

 The ester value, 

 which increased 

 somewhat during the 

 first year, increased 

 rapidly during the 

 second and third 

 years, indicating that 

 the esterification was 

 slightly in advance of 

 the formation of free 

 acids at all periods of 

 storage and became 

 more pronounced at 

 the close of the third 

 year. The iodin 

 value gradually increased, indicating the continuous formation of 

 unsaturated compounds in the soft resins throughout the entire period 

 of storage. The 

 saponification value 

 gradually increased 

 throughout the 

 period of storage. 



Figure 9 gives a 

 graphic illustration 

 of the various values 

 as found in the un- 

 sulphured hops in 

 cold storage. The 

 acid value gradually 

 increased throughout 

 the period of stor- 

 age. The ester value 

 diminished d u r i 1 1 g 

 the first year of stor- 

 age 1 , increased some- 

 what during the sec- 

 ond year, and in the third year the increase was rapid. Figure 1 9 

 shows also that esterification did not keep pace with the formation of 

 free acids during the first year of storage. However, during the next 



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Fig. 9. — Curves showing the correlation of chemical values of the soft 

 resins In unsulphured hops In cold storage. 



