CONCORD GRAPE JUICE. 
11 
the majority, however, the time allowed for the pressing is about 
one hour, including the 35 minutes for reaching high pressure of 
100 tons, and 25 minutes at high pressure, so that the entire pressing 
from the time the first layer is made through the settling period to 
the time the pressure is released occupies about one hour and 25 
minutes. 
Table 6 shows the differences in composition of the juices obtained 
at various pressures. 
Table G. — Chemical composition of Concord grape juices obtained at various pressures. 
Pressure. 
Experi- 
ment. 
Time. 
Solids, 
per 100 
cc. 
Sugars 
as in- 
vert be- 
fore in- 
version, 
per 100 
cc. 
Non- 
sugar 
solids, 
per 100 
cc. 
Ash, 
per 100 
cc. 
Total 
acid as 
tartaric, 
per 100 
cc. 
Total 
tartaric 
acid, 
free and 
com- 
bined, 
per 100 
cc. 
Tannin 
and 
coloring 
matter, 
per 100 
cc . 
1 
2 
1 
2 
1 
2 
1 
2 
1 
2 
Min. 
} - 
} - 
} - 
} « 
} 25 
Grams. 
/ 16.62 
\ 16. 78 
/ 17.30 
\ 16.91 
| 17.48 
Grams. 
13.48 
13.36 
13.82 
13.34 
13.86 
Grams. 
3.14 
3.42 
3.48 
3.57 
3.62 
Grams. 
0.410 
Grams. 
1.11 
1.04 
1.20 
1.17 
1.25 
Grams. 
0.99 
.99 
1.01 
1.06 
1.04 
Grams. 
0.27 
.26 
.28 
.28 
.31 
• 
75 to 100 tons 
r i7.4i 
\ 16.78 
/ 17.48 
\ 16. 73 
13.88 
13.07 
13.66 
12.93 
3.53 
3.71 
3.82 
3.80 
.484 
1.25 
1.28 
1.27 
1.31 
1.07 
1.15 
1.12 
1.17 
.33 
Drainings at 100 tons 
.29 
.36 
.32 
The data in Table 6 were obtained on hydraulic presses with 10-inch 
rams. The pulp was heated to about 150° F. and made into cheeses 
consisting of 10 layers, each 48 by 48 by 3 inches. The completed 
cheese was allowed to settle for about 15 minutes under the weight 
of the piston head. The juice expressed in this manner, which is 
i termed "free run," amounted to about 65 per cent of the total avail- 
able juice. Pressure was then applied, and gradually brought up to 
100 tons; from to 25 tons in about 15 minutes; from 25 to 75 tons 
in about 15 minutes; from 75 to 100 tons in about 5 minutes. At 
; 100 tons the pressure was held about 25 minutes, so that the total 
time of pressing after the cheese was prepared was about 1 hour 
; and 15 minutes. 
The data are self-explanatory. They show that as the pressure 
increases the juice becomes more fullbodied and richer in color and 
acid ingredients. 
After the cheese has been allowed to drain at high pressure the 
pressure is released. The residue in the cloths, called the pomace, 
amounts to about 15 per cent of the heated fruit. A pomace which 
has been subjected to 100 tons pressure is dry and tough. It con- 
tains, on an average, about 60 per cent moisture and 40 per cent 
