SOFT RESINS IN SULPHURED AND UNSULPHURED HOPS. 



17 



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two years it was more rapid, with a consequent increase in the ester 

 value. 



The saponification value gradually increased after the first year of 

 storage. The iodin value likewise increased after the first year, 

 although during that year it diminished somewhat, but during the 

 second year it increased rapidly, indicating thereby that the unsatu- 

 rated compounds formed in the soft resins also increased rapidly, and 

 they remained fairly constant after this point was reached until the 

 close of the third year. 



Figure 10 shows the various values as found in the unsulphured 

 hops in open storage. The acid value diminished slightly during the 

 first year and in- 

 creased each year 

 thereafter. The es- 

 ter value increased 

 slightly during the 

 first year, quite rap- 

 idly during the sec- 

 ond year, and re- 

 mained constant 

 during the third 

 year, esterification 

 in this sample prac- 

 tically keeping pace 

 with the formation 

 of free acids through- 

 out the storage 

 period. The saponi- 

 fication value, which 

 decreased slightly 

 during the first year of storage, increased during the second and third 

 years. The iodin value decreased slightly during the first year, in- 

 creased rapidly during the second year, and slightly during the third 

 year, indicating thereby that the unsaturated compounds in the soft 

 resins remained fairly constant during the first year, increased rapidly 

 during the second year, and were fairly constant during the third 

 year of storage. 



The relations of these various values may be briefly summarized as 

 follows : 



(1) A change took place in some of the components of the soft resins of the hops, 

 indicative of a marked rearrangement in these compounds during the period that 

 elapsed between picking the hops and the end of one year of storage. 



(2) This change was most pronounced in the hops~in cold storage, irrespective of 

 treatment at the dry kiln. However, on comparison, the unsulphured hops showed 

 the greatest change. 



Fig. 10. — Curves showing the correlation of chemical values of the soft 

 resins in unsulphured hops in open storage. 



