Hexane Extracted vs. Expeller Pressed
Mass market oils are typically extracted from seed using a petroleum product called hexane. Conventional manufacturers like hexane because it is highly efficient, pulling almost 100% of the oil from seed. Because hexane evaporates during processing, the FDA does not require it to be disclosed on the label. But some consumers are concerned about potential chemical residues, and hexane is notoriously harmful to the environment.
Natural oils are crushed from seed using the hydraulic action of an expeller press. Expeller pressing yields less oil than chemical extraction, usually about 50-70% of the oil, so expeller pressed oils are usually more expensive than conventionally processed oils. They are also much kinder to the environment.