—This is a purchasable product and is used at times as a substitute for oleo stearine.
Lard Oil.
—The production of lard oil used in compounding lubricating oils and illuminating oils is still carried on to some extent. The process consists of graining the oils in graining tanks or in seeding trucks similar to oleo oil graining trucks.
Pressing.
—The lard cooled to a temperature of 40° F. is placed in cloth wrapper arranged so that all oil is strained through the wrapper. The solid substance contained in the wrapper is lard stearine used to harden pure lard.
FIG. 158.—FILTER PRESS FOR LARD OR OLEO OIL.
Graining.
—After the fats have been washed they should be drawn into trucks or tierces and placed in a room where there is good ventilation, and kept there for about two days, giving the acid fumes an opportunity to pass off; the fat will then be found to be lowered to about 80° F. and should then be removed to a room that is refrigerated. After remaining in this temperature three or four days the fats will be found to be crystallized, or grained, and of about the temperature of the rooms. It is then ready to go to press.