THIRTY-THIRD BIENNTAT SESSION 
157 
THE CONCENTRATION OF FRUIT JUICES BY REFRIGERATION. 
H. C. Gore, Washington, D. C. 
About a year ago we were working on the problem of preparing orange 
juice. Some experiments were made, and in one of these we allowed the 
orange juice to freeze solid. 
The juice was in a three-gallon bottle, and we brought that out into 
the laboratory and allowed it to warm up. We found that upon melting, the 
ice had evidently loosened from the wall of the container and just a little 
remained floating on the surface. The lower layers of the juice consisted of 
a most delicious syrup, and at the top was a very watery solution containing 
almost no orange flavor. 
We noticed another change produced by the freezing; a peculiar co- 
agulation of the suspended matter of the juice occurred, and by carefully 
filtering off the coagulum we were able to get the juice perfectly clear. We 
have not pushed the study of coagulation by freezing any further, however. 
We quickly found out that if we crushed the frozen orange juice and 
centrifugalized it we could easily separate the delicious syrup, leaving the 
ice behind. We subsequently applied the method to a wide range of fruit 
juices. In all cases syrups of excellent fruit flavor were obtained. The 
process is of particular value applied to apple cider, as a product is obtained 
which ferments extremely slowly and which can be shipped and marketed 
without a preservative. 
I investigated the patent literature and found that the process of freez- 
ing, crushing and centrifugalizing was quite old. It is covered by two ex- 
pired patents. For some reason (probably because cold storage had not 
been very completely developed twenty-five years ago) these patents had 
never been utilized. We have just come back from field work at Hood 
River, Oregon, and I want to show a few slides which bring out the develop- 
ment of this work. Following this I wish to illustrate by use of this machine 
the operation of centrifugalizing the crushed frozen fruit juice, working 
with grape juice. You will then have an opportunity of tasting the concen- 
trated grape juice and cider. (Pictures shown.) 
We prepared about one hunderd gallons of the freezing-concentrated 
cider at Hood River and we have a sample of it here. It was shipped by 
express, without perceptible fermentation occurring. 
(Demonstrates the basket centrifugal machine, in operation.) 
This small basket centrifugal rotates at about two thousand four hun- 
dred r. p. m.; the larger size used in the field runs at about nine hundred 
x*. p. m., but the centrifugal force is much greater with the larger machine. 
It requires about three minutes’ operation, you see, to effect the necessary 
separation. 
Question: What temperature must be maintained? 
Mr. Gore: On the commercial scale we use brine temperatures of from 
0 degree to 10 degrees F. 
