6 
Journal of Agricultural Research 
Vol. II, No. i 
The foregoing results are regarded as typical of a well-ripened Roque¬ 
fort cheese. It is to be expected that a mild cheese will have a lower 
volatile acid number and a very ripe cheese a higher one. Analyses of 
the acid distillates of cheeses of differing degrees of ripeness have been 
made and are summarized in Table IV. 
Table IV. —Volatile acids in ioo grams of cheese . 
[Acidity in decinormal c. c.I 
No. 
Condition of cheese. 
Total 
volatile 
acids. 
Insoluble 
acids. 
Soluble 
acids. 
Caproic 
acid. 
Butyric 
acid. 
Acetic 
acid. 
Add num¬ 
ber for 10 
grams of 
fat. 
I 
Slightly rip¬ 
ened . 
15- °7 
2. 90 
12. 17 
6.85 
4. 14 
1. 18 
2 
Well ripened. ., 
45* 09 
8. 10 
36- 99 
I 3- 34 
19.05 
4. 60 
56.4 
3 
Overripened.... 
102. 23 
29.30 
7 2 - 93 
30-38 
36- 3° 
6.25 
152.6 
For the determination of the insoluble-acid number of io grams of fat 
reported in the above table, the procedure of Schmid-Bondzynski 1 was 
followed. The cheese was digested in warm hydrochloric acid of a 
specific gravity of 1.125 until the fat separated. It was then washed free 
from hydrochloric acid, was dried and filtered clear. A sample of the 
fat was weighed out, dissolved in 95 per cent alcohol, and titrated with 
decinormal sodium hydroxid. The result was calculated to 10 grams 
of fat. 
In order to follow up the increase in acidity of the distillate during 
progressive ripening, about 1 pound of cheese was minced and placed in 
a large bottle. A 50-gram sample was immediately weighed out and 
distilled. The cheese was kept at about 23 0 C., and on the dates given 
in Table V the mass was thoroughly mixed and other 50-gram samples 
were taken and distilled. During this time the cheese developed no 
abnormal flavors. 
Table V .—Volatile acids in 100 grams of cheese. 
[Acidity in decinormal c. c.I 
Date. 
Total vola¬ 
tile adds. 
Insoluble 
adds. 
Soluble 
adds. 
Caproic 
acid. 
Butyric 
acid. 
Acetic 
acid. 
Mar. 16. 
44. 52 
8. 64 
35- 88 
12. l6 
21. 56 
2. l6 
Mar. 18. 
ZO . 02 
II. 30 
38. 72 
12. 96 
21. 12 
4. 64 
Mar. 22.. 
0 
79. 08 
22. 20 
57 * 78 
20. 04 
32. 64 
5.10 
Apr. 1. 
/ 7 7 
122.60 
33- 20 
89. 40 
38. 88 
46. 20 
4 - 52 
1 See Barthel, Chr. ( 2 , p. 187). 
