CLARIFICATION TESTS. 15 



that sterilization should be effected either by bringing the juice to a 

 higher temperature than 65 C. or by heating for a longer time than 

 thirty-five minutes. It will be noted that the three juices which are 

 low in acid spoiled, namely, the Tolman, the Shockley, and the Gilpin, 

 as well as those containing moderate amounts, as, for example, the 

 Ben Davis and Rails, plainly indicating the influence of acid in 



assisting sterilization. 



IN GLASS. 



In 1906 an extended series of experiments was conducted to 

 determine the best treatment for sterilizing in bottles. The 

 results showed that heating for one hour at 149 F. (65 C.) in a 

 water bath gave good results, and that heating one-half hour at 

 158 F. (70 C.) was also a satisfactory process, allowing in each case 

 a half hour for the contents of the bottles to attain the bath tem- 

 perature. The products could be processed for as long as one hour 

 at 158 F. without any marked deterioration, allowing a half hour 

 for preliminary heating, thus making the total time in the water 

 bath one and one-half hours. A very important consideration in 

 the case of bottled apple juice is the removal of the sediment. The 

 milk separator (see page 16) will remove the greater part of the 

 sediment when operating on freshly expressed juice. It does not, 

 however, remove. all, so that a brilliant juice is not obtained when 

 clarified in this way. The product is still slightly turbid and gradually 

 deposits a sediment which much impairs the appearance of the cider. 

 Further experiments on sterilizing in glass have been deferred, 

 chiefly because it is felt that there is less need of investigation in this 

 direction than along the line of preparing sterilized apple juice in 

 wood and tin containers. 



CLARIFICATION TESTS. 

 METHODS EMPLOYED. 



Freshly expressed apple juice normally contains considerable 

 quantities of insoluble matter. This is true of all apple juices which 

 have been used except Kentucky Red, which was almost free from 

 such material. This insoluble material consists largely of albumi- 

 nous matter, starch grains, and yeast- cells, together with some dirt 

 particles, all of which settles on the bottom of the container, forming 

 a thick, brownish layer. As has been stated, the simplest way of 

 removing the greater part of this material is by the use of the milk 

 separator, as was demonstrated in the experimental work of 1906. 

 This method, however, can only be successfully practiced with abso- 

 lutely fresh juice. 



In the experiments of 1907, owing to the local conditions at the 

 mill where the apples were pressed, it was necessary to grind at night, 



