CONCORD GRAPE JUICE. 
METHODS OF ANALYSIS. 
25 
Solids: From the specific gravity and the alcohol content. The 
specific gravity was obtained from the Brix reading at 17.5° C. 
Alcohol: By immersion refractometer. 
Nonsugar solids: From solids and sugars before inversion. 
Acid,: Spotted into litmus solution. 
Polarizations: On solutions clarified with normal lead acetate. 
Total tartaric acid: Hartmann and Eoff method (U. S. Dept. Agr., 
Bur. Chem. Bui. 162: 72). 
Free tartaric acid and cream of tartar: Calculated from total tartaric 
acid and the alkalinites of the ash (U. S. Dept. Agr., Bur. Chem. 
Bui. 162:75). 
Tannin and coloring matter: Loewenthal's method. 
ADDITIONAL DETERMINATIONS. 
In the course of the investigation a number of determinations not 
incorporated in the tables of composition were made. These results 
are given in Table 12. 
Table 12. — Additional chemical determinations of constituents of Concord grape juice. 
Group. 
P 2 0i. 
CI. 
S0 3 . 
Volatile 
acid as 
acetic. 
Nitrogen. 
1 
Mg. per 
100 cc. 
J 24.2 
\ 21.2 
f 16.9 
J 15.5 
i 16.7 
I 17.7 
f 17.5 
19.0 
20.6 
20.0 
15.6 
18.0 
21.1 
23.6 
22.3 
21.3 
17.6 
19.5 
18.6 
21.8 
19.0 
20.2 
39.7 
35.7 
36.9 
38.1 
39.7 
41.2 
39.4 
Grams per 
100 cc. 
0. 0025 
.0018 
Grams per 
100 cc. 
Grams per 
100 cc. 
Grams per 
100 cc. 
0.01 
.01 
.01 
.01 
2 
.0018 
.0018 
0. 0080 
.0116 
3 
.01 
.01 
.0014 
.0021 
.0082 
.0075 
.01 
.01 
.01 
.0021 
.0018 
0.051 
.0089 
.01 
.01 
5 
.0025 
.0025 
.0021 
.054 
.054 
.043 
.02 
.04 
.04 
.03 
.02 
.02 
.03 
6 
The volatile esters were also determined on 19 samples from the 
six different factories, and found to range between 0.12 and 0.23 
gram per 100 cubic centimeters, with an average of 0.16 gram per 
100 cubic centimeres. 
