16 
BULLETIN 656, U. S. DEPARTMENT OF AGRICULTURE. 
change from the supersaturated to the saturated condition is very 
gradual, so that the time allowed for the precipitation has a decided 
effect upon the amount of cream of tartar retained in solution. 
This is shown in Table 9, wherein it will be noticed that the cream of 
tartar content has diminished during the additional one year of 
storage. Shaking a grape juice hastens the precipitation of cream 
of tartar, and brings about an equilibrium much more rapidly than 
simply allowing the juice to stand undisturbed. It seems therefore 
that the process of manufacture could be shortened, if after a few 
days' storing the juice were given a thorough shaking, and then 
allowed to stand for the rest of the storage period. It also seems 
reasonable to believe that this extra manipulation would give a 
much brighter finished product. 
Table 9. — Chemical composition of Concord grape juice after 4 months' storage and after 
16 months' storage. 
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Storage period. 
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Months. 
Gms. 
Perct. 
Gms. 
Gms. 
Gms. 
GmS. (? 
ms. 
Gms. 
Gms. 
Gms. 
Cc. 
Cc. 
Gms 
4 
17.43 
0.07 
14.45 
14.40 
2.98 
0.95 
OS 
0.15 
0.58 
031 
31.0 
4.2 
0.16 
16 

17.48 
.07 
14.60 
14.70 
2.88 
.94 
67 
.20 
.51 
.25 
27.0 
4.6 
.14 
4. 
16.47 
.13 
13.87 
13.82 
2.60 
.83 
65 
.13 
.57 
.31 
30.4 
4.4 
.13 
16 

16.47 
.14 
14.00 
13.98 
2.47 
.83 
60 
.16 
.49 
.26 
25.8 
3.8 
.12 
4. 
17.85 
.05 
14.42 
14.36 
3.43 
1.10 
82 
.27 
.58 
.35 
30.8 
5.8 
.26 
16 

17.80 
.07 
14.54 
14.64 
3.26 
1.06 
72 
.28 
.41 
.26 
21.6 
7.6 
.20 
4. 
19.00 
.07 
15.70 
15.77 
3.30 
1.11 
69 
.28 
.43 
.23 
23.0 
4.4 
.33 
16 

19.10 
.07 
15.90 
15.95 
3.20 
1.14 
65 
.27 
.35 
.22 
18.6 
7.0 
.16 
4. 
18.53 
.06 
15.06 
15.06 
3.47 
1.13 
83 
.33 
.54 
.28 
28.8 
4.6 
.33 
16 
18.48 
.07 
15.20 
15.30 
3.28 
1.10 
70 
.31 
.38 
.22 
20.0 
6.0 
.16 
4. 
18.79 
.13 
15.48 
15.68 
3.31 
1.13 
79 
.29 
.55 
.30 
29.0 
4.4 
.22 
16 
18.80 
.07 
15.60 
15.58 
3.20 
1.14 
66 
.28 
.36 
.23 
19.4 
6.2 
.17 
4. 
17.85 
.07 
14.30 
14.43 
3.55 
1.19 
88 
.37 
.56 
.34 
30.0 
4.2 
.32 
16 
17.80 
.07 
14.55 
14.49 
3.25 
1.20 
80 
.41 
.38 
.24 
20.0 
6.0 
.17 
4. 
18.95 
.20 
15.47 
15.41 
3.48 
1.09 
75 
.22 
.56 
.31 
29.6 
6.0 
.32 
16 

18.87 
.13 
15.64 
15.64 
3.23 
1.10 
68 
.26 
.41 
.25 
21.8 
6.0 
.17 
Maximum: 
4 
19.00 
.20 
15.70 
15.77 
3.55 
1.19 
88 
.37 
.58 
.35 
31.0 
6.0 
.33 
16 
19.10 
.14 
15.90 
15.95 
3.28 
1.20 
80 
.41 
.51 
.26 
27.0 
7.6 
.20 
Minimum: 
4 
16.47 
.06 
13.87 
13.82 
2.60 
.83 
65 
.13 
.43 
.23 
23.0 
4.2 
.13 
16 
16.47 
.07 
14.00 
13.98 
2.47 
.83 
60 
.16 
.35 
.22 
18.6 
3.8 
.12 
Average: 
4 
18.11 
.10 
14.84 
14.87 
3.27 
1.07 
76 
.26 
.55 
.30 
29.1 
4.8 
.26 
16 
18.10 
.09 
15.00 
15.04 
3.10 
1.06 
69 
.27 
.41 
.24 
21.8 
5.9 
.16 
A veraee loss 
.01 
.0! 
.17 
.01 
07 
.14 
.06 
7.3 
.10 
Small amounts of alcohol have a decided effect on the general 
clarification of a juice, lowering the viscosity and insuring a better 
precipitation of cream of tartar. Table 11, group 2, shows that 
