UTILIZATION OF GRAPE POMACE AND STEMS. 11 
In the manufacture of jelly it is absolutely necessary that the 
jellifying strength of a given juice be fairly accurately known, on 
account of the interdependence of the percentage content of the 
pectin, sugar, acid, and water. Varying the quantity of any one of 
these may cause the difference between good and poor jelly from the 
standpoints of texture and taste. It should always be recognized 
that it is impossible to determine the character of the resulting jelly 
until it has cooled under ordinary atmespheric conditions. Usually 
the results of a given procedure are not known until the following 
day. : 
The pectin is controlled by varying the quantity of juice used. 
The sugar should be increased or decreased as is found necessary for 
the given quantity of juice. Too little sugar produces tough, rub- 
bery jelly, while too much produces soft jelly. To ascertain the best 
proportion of sugar to use to a given quantity of juice, it is recom- 
mended that a known weight of the pomace be cooked with the same 
relative quantity of water that is regularly used in the process of 
jelly manufacture. Add dissolved tartaric acid to the juice in the 
proportion of 1 ounce of acid to 1 gallon-of juice. Divide this juice 
into equal portions of 1 pint each. For each pint use, respectively, 
one-fourth, one-half, three-fourths, and 1 pound of sugar. Cook to 
224° F., pour into jelly glasses, and set aside undisturbed until the 
next day. The boiling should be done over a good flame and in a 
vessel large enough to take care of the excessive foaming. 
These samples should be concentrated within 20 minutes, since 
long, slow boiling destroys the jellifying qualities. The jelly that 
presents the best texture is the one to adopt as the standard: How- 
ever, the relative quantities of sugar and juice should be confirmed 
by making a larger batch, since results obtained from small quan- 
tities are not always the same when applied to large commercial runs. 
Any kind of sugar, whether cane, beet, or one of the corn sugars, 
such as glucose and the hke, may be used. 
All jelly should possess more or less acidity. Jelly of the best 
quality possesses an acidity of approximately 0.75 per cent (ex- 
pressed as tartaric acid). Too little acidity results in soft jelly; too 
great an acidity also produces soft jelly, because it destroys the jelh- 
fying properties of the juice during the boiling operation. Since 
most of the acid in the grapes is removed with the juice, it, is neces- — 
sary to add tartaric acid to restore the acidity sufficiently to estab- 
lish the proper ratio for satisfactory jelly. In all cases the acid 
should be dissolved in the smallest possible quantity of water and 
added to the boiling mass; otherwise it may not readily go into 
solution. 
The water content, of course, is regulated by the extent to which 
the mass is evaporated and is best determined by the boiling tem- 
