PRODUCTION AND UTILIZATION OF FATS AND OILS 15 
peanut-growing sections and only a small additional investment is 
required for the equipment needed for cleaning and shelling the nuts. 
The utilization of cottonseed-oil mills saves the expense of separate 
buildings and equipment. 
COLD PRESSING 
To obtain a very pale cold-pressed oil, the kind preferred by 
Europeans, the red skins must be removed before pressing. In the 
United States it is customary to cold press the shelled nuts without 
separating the red skins. An excellent oil, with a color somewhat 
deeper than that of the oil expressed from decorticated kernels, is 
thus obtained. 
To express the oil by the hydraulic press, the kernels must be 
passed through rolls to crush the oil cells as thoroughly as possible, 
but leaving the product in a suitable condition for the extraction 
of the oil. When the oil is to be expressed by the continuous working 
oil expeller, the kernels are frequently first crushed to a coarse meal. 
If the kernels have not been crushed before being passed through 
the expeller, the cake is ground and pressed again for a further 
recovery of the oil. In Europe, where the hydraulic press is com- 
monly employed, the cake, after cold pressing, is ground, moistened, 
cooked, and hot pressed. 
HOT PRESSING 
Most of the peanut oil produced in this country is obtained by 
hot pressing. The crushed nuts are heated or " cooked " in a cotton- 
seed or other cooker before expressing the oil. 
Formerly, unshelled nuts were crushed and pressed, but this prac- 
tice yielded less oil because of the absorbent character of the shells. 
REFINING 
The hot-pressed oil is refined by the caustic-soda process, bleached, 
and deodorized in a manner similar to the refining of cottonseed 
oil (p. 6). The refining of peanut oil requires experience, which 
can be obtained only at a refinery, partly because different shipments 
of oil may vary in character, so that the refining procedure must be 
modified to obtain satisfactory results. 
Grades 
The following well-defined grades of peanut oil have been estab- 
lished by the Interstate Cotton Seed Crushers' Association : 6 
CRUDE OIL 
Choice crude peanut oil. — Choice crude peanut oil must be pressed and not 
extracted, from sound peanuts, must be sweet in flavor and odor, free from 
water and settlings, and shall produce, when refined as required by these 
rules, choice yellow peanut oil with a loss in weight not exceeding 3 per cent. 
Prime crude peanut oil. — Prime crude peanut oil must be pressed and not 
extracted, from sound peanuts, must be sweet in flavor and odor, free from 
water and settlings, and must produce prime yellow peanut oil when refined 
8 Interstate Cotton Seed Crushers' Association, rules governing transactions 
between members of the interstate cotton seed crushers' association. p. 10-12. 
[n. p.] 1925. 
