14 BULLETIN 1475, U. S. DEPARTMENT OF AGRICULTURE 
SECOND AND THIRD PRESSING 
The press cake is ground and a second pressing is made at a 
pressure much higher than that used in the first pressing. Most of 
the oil is obtained in the second pressing. It is of good quality and 
is usually combined with oil of the first pressing. The press cake 
with the pits is ground again with a little hot water and pressed 
at a still higher pressure. Oil obtained by such a third pressing is 
classed as inferior to strictly cold-pressed oil. 
EXTRACTION 
In Europe the oil remaining in the press cakes is extracted with 
volatile solvents, such as carbon disulphide, benzene, gasoline, and 
trichlorethylene. The extracted oil, from which the solvent has been 
removed, is known as sulphur olive oil or extracted olive oil, and 
is imported into the United States as olive oil foots. 
Uses 
Olive oil is highly esteemed as a salad oil, and it is also widely 
used medicinally. Olive oil foots are imported into the United 
States principally for making soap. The press cake is utilized chiefly 
for boiler fuel and for supplying humus to orchards. 
PEANUT OIL 
The peanut is an important crop in the United States as well as 
in Africa, China, India, and Japan. Farmers' Bulletin 1127 4 
describes the varieties grown in this country. The Spanish type, 
which can be cultivated under a wider range of soil and climatic 
conditions than the other varieties, is the one usually grown here 
for the production of oil. 
The quantity of peanuts crushed for oil in the United States 
varies greatly from year to year with the market demand for the 
nuts for other purposes. When the, price of peanuts is so high as to 
prohibit their general use for pressing, nuts discarded by the shelling 
plants are the principal sources of the oil. 
Preparation 
Department of Agriculture Bulletin 1401 5 discusses in detail the 
preparation of peanut oil. High-grade oil is made only from sound, 
well-matured peanuts and by employing only careful methods ot 
manufacture and storage. Large quantities of low-grade nuts which 
accumulate at the cleaning and shelling plants are also pressed. 
Some of the oil thus obtained is refined for edible purposes. The 
lowest-grade oil goes to the soap maker. This practice of utilizing 
discarded peanuts for oil is a distinct advantage to the industry, un- 
less the oil is sold for purposes to which it is not adapted. 
Cottonseed-oil mills are used largely in the manufacture of peanut 
oil for the reason that these mills are frequently near, if not in, the 
* Bbattie, W. R. peanut growing for profit. U. S. Dept. Agr. Farmers' Bui. 1127, 
33 p., illus. 1920 
B Clay, H. J., and Williams, P. M. marketing peanuts. U. S. Dept. Agr. Bui. 1401, 
99 p., illus. 1926. 
