May 25, 1914 
Aroma of Hops 
125 
Table III .—The acid , ester, and saponification numbers of hop oils distilled during 
several seasons . 
Sources of hops. 
Acid numbers. 
Ester numbers. 
Saponification numbers. 
1906 
1907 
1908 
1909 
1910 
Av¬ 
er¬ 
age. 
1906 
1907 
1908 
1909 
1910 
Av 
er¬ 
ase. 
1906 
1907 
1908 
1909 
1910 
Av¬ 
er¬ 
age. 
California: 
Perkins No. i. 
0.0 
r -5 
1.1 
0.86 
42.0 
47.0 
47-1 
45*5 
42.0 
48*5 
48. 2 
.... 
46.2 
Cosnmne. 
. 0 
2.4 
2.9 
1. 76 
45*o 
46.0 
51*0 
47*3 
45*o 
48.4 
53*9 
.... 
49*1 
Perkins No. 2. 
1.6 
2.0 
1.80 
45*o 
43*7 
44*3 
46.6 
45*7 
.... 
46.1 
Ukiah. 
.0 
1.1 
1.8 
.96 
40.8I44.0 
5i*o 
45*2 
40.8 
4S* 1 
52*8 
.... 
46.2 
Wheatland. 
2*3 
2.0 
1.4 
1.90 
50*0 
45*5 
41.0 
45*5 
52*3 
47*5 
42*4 
47*4 
Oregon. 
5*5 
1.6 
1.0 
2.8 
2. 70 
72.0 
57*o 
50. 2 
56.0 
58.8 
77*5 
58.6 
51*2 
58.8 
61.5 
New York. 
4-6 
3-6 
2.1 
2*5 
3*25 
44.0 
61. 0 
47*o 
51*8 
50-9 
48.8 
64.6 
49*i 
54*3 
54*2 
Washington. 
1.0 
i-5 
1.25 
.... 
51*8 
53* S 
52.8 
S2.8 
55*3 
54*o 
Imported (Saaz). 
i-5 
I- 5 
1.0 
3*o 
3* 1 
2. 02 
12.6 
20.0 
36.0 
28.6 
20.4 
23*5 
14.1 
21*5 
37*o 
31.6 
23* sj21* 
The oils, in the order of their average acidity, were as follows: New 
York, Oregon, imported, California, and Washington. In every instance 
the New York oils showed comparatively high acidity. Whether this 
high acidity content was inherent in the oil or whether it was due to 
conditions of drying and storing can not be stated. The high acidity 
seemed to be general, since two other samples of New York hops (not 
recorded) yielded oils with the acid numbers 2.6 and 3.2, respectively. 
The average acidity of the Oregon hop oil as given is probably some¬ 
what high, as it was considerably augmented by the high acid number 
of the oil from the 1906 crop, which was distilled from a sample of hops 
that were not in as fresh condition as the 1907, 1908, and 1909 hops. 
The oils from the imported hops were somewhat lower than those from 
the Oregon hops, being fairly constant in 1906, 1907, and 1908, but 
much higher in 1909 and 1910. These were followed by the California 
and Washington oils, with an average of 1.41 and 1.25, respectively. 
The high and low acid numbers were significant of nothing important 
as far as the aroma was concerned, as the free acidity did not perceptibly 
affect the odor of the oil. 
The ester numbers revealed most striking similarities and dissimi¬ 
larities, not only during one season but for several successive seasons. 
It was to be expected that the oils from the hops during any one season 
would show differences, but that these same differences should appear 
during three, four, and even five successive seasons was most surprising. 
The oils from the imported hops were conspicuous because of the fact 
that the data for the several seasons showed the ester content to be 
only about one-half as great as the ester content of the oils from the 
California, Oregon, Washington, and New York hops. Besides the 
samples recorded in the table, a cold-storage sample of Saaz hops of the 
1906 crop, distilled one year later, gave an oil with an ester number of 
41217 0 —14-4 
