I: Extraction Methods

Centrifugal
Where raw materials are mixed with hot water and separated by a three way centrifuge into solids, oil, and water.

Expeller (Screw) Press
A continuous feed method where oil is squeezed from the raw material in one step under high pressure.

Hydraulic Press
A batch-type method which operates like an ordinary machine shop press. Oil is squeezed out of the compressed oil seed.

Solvent
Where the raw material is soaked and dissolved in solvent (i.e. Hexane) forming a mixture called miscella. This miscella drains from the cake where the solvent is removed by evaporation.

Alkaline Refining
The process of reacting caustic soda with the free fatty acids in crude oil to form an oil insoluable soap. This soap is then separated along with other impurities from the neutral oil.

Bleaching
Mixing activated earth or carbon with refined oil to remove the remaining color pigments, heavy metals, and traces of soap. The bleaching media is then removed by filtration.

Deordorizing
Passing refined oil over heated trays in an evacuated vessel. The oil then spills from one tray to the next and in doing so loses its smell and some color.

Filtering
After extraction, when the crude oil is filtered either with clay, paper, or charcoal to remove impurities such as seed fragments and meal fines. This process improves oil clarity and odor.

Winterizing
The process of cooling an oil to a given temperature so that crystals that may have been formed can be filtered out.