SOFT RESINS IN SULPHURED AND UNSULPHURED HOPS. 



11 



AH the samples had an extremely bitter taste, manifested, strongly 

 at the base of the tongue when a minute particle of the soft resin was 

 held in the mouth for a few seconds. 



The color, odor, and taste, which appeal solely to the senses, are of 

 relatively small importance in this investigation. As shown in Table 

 VIII, the color of the soft resins in all cases became darker with the 

 age of the sample examined; the odor became very disagreeable with 

 the decrease of the soft resins and the taste at all times remained very 

 bitter. 



The soft resins are fluid in nature, and during the first two years of 

 storage all were of the same consistency. Those extracted in 1914 

 were more solid and had the consistency of a thick sirup. Owing to 

 their nature, the specific gravity of these resins could not be deter- 

 mined with accuracy. 



ACID AND ESTER VALUES. 



The determination of the free acidity or acid value of the soft 

 resins was carried out as follows: A small quantity of weighed soft 

 resin was taken up in 2 c. c. of standardized alcoholic potassium 

 hydroxid and the excess potassium hydroxid titrated back with N/10 

 hydrochloric acid. The acid value represents the number of milli- 

 grams of potassium hydroxid necessary to completely neutralize the 

 free acids in 1 gram of the soft resins. 



In determining the ester value of the soft resins a weighed portion 

 was taken up in standardized alcoholic potassium hydroxid and 

 allowed to stand 24 hours in the cold. Complete saponification took 

 place in that length of time. The excess alkali was titrated back 

 with N/10 hydrochloric acid and the saponification value calculated. 

 This value, minus the acid value, gives the ester value of the soft 

 resins and represents the number of milligrams of potassium hydroxid 

 necessary to completely saponify all the combined acids in 1 gram 

 of the soft resins. The changes observed in the acid and ester values 

 are shown in Table IX. 



Table IX. — Acid and ester values of the soft resins in the original samples of sulphured 

 and unsulphured hops and in samples kept in cold and in open storage. 



Treatment at the kiln. 



Acid value: 



Sulphured. . - 



Unsulphured 

 Ester value: 



Sulphured. . . 



Unsulphured 



Original 



sample, 



1911. 



71.80 

 60.87 



97.7 

 121. 78 



Cold storage. 



97.00 

 67.00 



169.5 

 71.5 



1913 1914 



87.50 

 76.50 



191.1 

 87.0 



80.7 

 76.2 



226.3 



207.8 



Open storage. 



1912 1913 



72.5 

 52.0 



122.5 

 123.5 



61.50 

 70.00 



202.5 

 158.0 



47.0 



77.6 



271.0 

 158.4 



