


SOFT RESINS IN SULPHURED AND UNSULPHURED HOPS. 15 
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 
im chouresie779 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 
z value gradually in- 
creased throughout 
SOOINE VALUE 

7 os 
YEARS 11 STORAGE 
Fia. 6.—Iodin-value curves of the soft resins in sulphured and un- 
sulphured hops in cold and in open storage. 



/ 2 
EARS 7 STORAGE 
Fig. 7.—Curves showing the correlation of chemical values of the S 
soft resins in sulphured hops in cold storage. the storage per lod. 
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. 
