8 BULLETIN 904, U. S. DEPARTMENT OF AGRICULTURE. 



of vanes on the inside of the cylinder is carried partly up the side 

 and then tumbled back among the pipes. These driers appear to 

 be efficient and are generally used for this purpose. Improvements 

 have been added from time to time, but the basis of operation is 

 the same. After, being dried, the germs are ready to go to the ex- 

 pelling plant. 



EXPELLING THE OIL FROM CORN GERMS. 



While the method of handling and degerminating the corn is 

 totally different in the dry and the wet processes, the operation 

 involved in handling the germ material after it is dried and ready 

 for the oil machinery is the same for both processes. At this point 



Fig. 7.— A type of moisture expeller used for wet corn germs and feed. 



it is logical to discuss the difference in the germ material as obtained 

 by the two processes. 



The germs separated by the dry process contain considerable 

 portions from other parts of the corn, which on an average reduce 

 the oil content to about IS per cent. Approximately 6 per cent of 

 oil remains in the cake. Dry-corn millers agree that half a pound 

 of oil is an average yield from a bushel of corn, and if 12 per cent of 

 oil from the germ is representative it follows that 4.17 pounds of 

 germs are obtained from a bushel of corn. 



The germs separated by the wet process are much cleaner — that 

 is, they contain much less of the other parts of the corn, and there- 

 fore average a much higher percentage of oil, or about 45 per cent. 

 It is not usually possible, however, to obtain a cake with as low an 

 oil content as that obtained by the dry process. The cake usually 

 contains about 9 per cent of oil. Assuming that 1{ pounds of oil 

 represent the average yield from a bushel of corn, and that 36 per 

 cent is obtained from the germ, the germ material obtained from a 

 bushel of corn must be about 3.47 pounds. 



