2 BULLETIN 1096, U. S. DEPARTMENT OF AGEICULTTJRE. 
CRUSfflNG PEANUTS. 
VARIETIES USED.2 
The Spanish variety is the one grown principally for the production 
of oil. The meats of this variety have a higher oil content than those 
of any other, with the possible exception of the Valencia, or Tennessee 
red. It has a higher proportion of meats to hulls than any other 
variety and is adapted to a wider range of soil and climatic conditions. 
PROCESSES. 
Most of the crushing of peanuts is done in cottonseed-oil mills, 
which are well adapted to this work. These mills run for part of 
the season on cotton seed, when it is available, and for another part 
of the season on peanuts. Thus a close relationship exists between 
the cottonseed-oil industry and the peanut-oil industry, although 
many mills crush peanuts exclusively. 
The processes for crushing peanuts in this country are of two dis- 
tmct types — the hydraulic, which is intermittent, and the expeller, 
which is continuous. 
HYDRAULIC PROCESS. 
From the storehouses to which they are brought by the farmers the 
peanuts are run through shakers or conveyors having fine sieves, to 
remove the sand and fine dirt, and then through larger sieves, con- 
sisting of perforated plates having holes large enough to permit the 
peanuts to drop through, thus separating them from the sticks, 
vines, stones, and larger pieces of trash, which pass out from the tail 
of the machine. 
The peanuts are next taken in screw conveyors to the huller. 
Sometimes this is an ordinary cottonseed bar huller, or a slight 
modification of it, consisting of a cylinder the lower part of which 
is made of sharp-edged steel bars, with revolving sharp-edged bars 
attached to a frame within. The peanuts are chopped as they pass 
between the sharp edges, and the meats and hulls pass out through 
slits between the bars. Most mills, however, use the so-called disk 
huller. This consists of a cyhnder the lower half of which is made of 
steel bars properly spaced, having inside rough-faced disks, some re- 
volving and others stationary, placed side by side, so that the revolv- 
ing disks alternate with the stationary disks. Peanuts are fed in at the 
top, the hulls are rubbed off as they pass between the disks, and the 
hulls and meats pass out through the slits between the bars below. 
The stock is next conveyed to a shaker machine, where the meats 
are separated from the hulls by means of sieves and an adapter 
2 A complete description of the varieties of peanuts grown in the United States is given in Fanners' 
Bulletin 751, copies of which may be had on application to the Division of Publications, U. S. Department 
of Agriculture, Wasliington, D. C. 
