utilizatio:n' of grape pomace and stems. 11 



In the manufacture of jelly it is absolutely necessary that the 

 jellif3'ing 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 

 standjDoints 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 ordinar}- atmospheric 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 jell}', while too much produces soft jell}'. 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 da3^ 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 cjuantities 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 like, 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 jelli- 

 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 quantit}- of water and 

 added to the boiling mass; otherwise it may not readily go into 

 solution. 



The Avater content, of course, is regulated by the extent to which 

 the mass is evaporated and is best determined by the boiling tern- 



