THE-PRODUCTION OF CORN OIL. 11 
a day for each press. These figures do not include the cost of re- 
pairing the cloths, which must constantly be done in order to make 
the set last 60 days. In the expellers this expense is eliminated. 
It is estimated that the cost of repairs on an expeller amounts to 
about $200 a year, or about 66 cents a day. It is evident, there- 
fore, that the replacing of parts in the expeller costs less than the 
press cloths for a press. 
It is estimated that the presses will deliver 1,400 pounds of oil 
in a 24-hour run, which is the oil equivalent of about 1,000 bushels 
of corn when degerminated by the wet process. The expeller will 
deliver 3,000 to 4,000 pounds of oil in 24 hours, or the equivalent of 
2,400 to 3,000 bushels of corn. The capacity of the expeller, therefore, 
is much greater than that of the press. However, the power required 
to operate the expeller is much greater, and the depreciation of the 
machine is also greatly in excess of that of the presses. The one 
great advantage of the press over the expeller is the exceedingly 
low upkeep and the practically indestructible character of the 
machine. 
HANDLING AND DISPOSING OF THE CRUDE OIL. 
FILTERING. 
Crude corn oil as it comes from the exyellers or presses is pumped 
through filter presses, which remove the fine meal and other sediment 
which has had time to settle. It is then placed in storage tanks until 
shipped. 
BUYING AND SELLING. 
Operators who do not themselves refine the oil sell it to refiners, 
soap makers, brokers, and in some cases to bakers. The use of crude 
corn oil for industrial and edible purposes will be considered later. 
The price obtainable depends largely on the grade of the oil, and 
especially on the amount of free fatty acids present. Prime crude 
oil is usually limited to not more than 2 per cent of free fatty acids. 
The next lower grade must not as a rule contain more than 3.5 per 
cent. Refiners protect themselves from a heavy refining loss by 
paying less for an oil which contains such acids in excess of the 
specified quantity. Under normal operating conditions with average 
corn the crude oil contains from 1 to 3 per cent of free fatty acids. 
It appears that the oil from wet-process germs has a somewhat higher 
percentage of free acids than that obtained from dry-process germs. 
Large refiners, in order to have enough to supply the demand for 
their refined oil, have found it profitable to buy considerable quan- 
tities of the crude oil and refine it in addition to their own production. 
Producers who market their refined oil as package goods for the 
retail trade find this practice especially desirable in order to supply 
the demand created by their extensive advertising. This practice 
