How is CASTOR oil extracted
Castor Oil is derived from the ripe beans of the Castor plant by either the cold or expeller pressing method or through solvent extraction; neither grinding nor tempering can be applied to Castor seeds the way it is applied to Flax Seeds or Soy Beans.
In the industrial process of extraction, the cleaned beans are first passed through machines that remove their outer coats. The more thorough this part of the process, the lighter the resulting oil. The Castor beans are then placed in a cage press through which the crude oil is obtained. This oil is refined and bleached. The final Castor Oil is colorless or pale-yellow in color. The final oil can be stored for up to 4 years.
A press-cake develops throughout the pressing process, and any remaining oil in the cake is extracted through the use of solvent extraction. This oil is called “Number III Oil.” It is not pure, and it cannot be successfully refined.