Clarification of the Oil
Filtering will remove insoluble contaminants such as fibre but the remaining oil will also contain moisture, resins and colorants from the seed. Clarification is a relatively simple method of removing these unwanted elements and can be done by letting the oil stand undisturbed for a few days and then separating the upper layer, or by using a clarifier in which the oil is held in a tank with a heat source.
The oil is boiled to drive off water and to destroy naturally occurring enzymes and contaminating bacteria. After heating, the oil is allowed to stand and the contaminants separate out. The oil is filtered through a cloth and is reheated to ensure that all the moisture has been removed.