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 6. — 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. 

 J 16.62 

 I 16. 78 



/ 17.30 

 \ 16.91 



f 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 



to 25 tons 



.26 

 .28 





.28 

 .31 







75 to 100 tons 



/ 17.41 

 \ 16.78 



f 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 

 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 



