How Are Seed Oils Extracted?

Seed oils are extracted using two primary methods: solvent extraction and mechanical extraction with a screw press.

Seed Oil Extraction Methods

This method involves using a solvent, typically hexane, to dissolve the oil from the seed.

Process Overview:
1. Seeds are cleaned and prepared.
2. Prepared seeds are mixed with the solvent.
3. The solvent dissolves the oil, creating a mixture called miscella.
4. The miscella is separated from the remaining seed material (meal).
5. The solvent is evaporated from the miscella, leaving behind the crude oil.
6. The crude oil is further refined to remove impurities.

This method uses a screw press to physically squeeze the oil out of the seeds.

Process Overview:
1. Seeds are cleaned and sometimes dehulled.
2. The seeds are fed into a screw press.
3. The screw press applies pressure, crushing the seeds and releasing the oil.
4. The oil is collected, and the remaining seed material (cake) is expelled.
5. The extracted oil may undergo further filtration and refining.

Feature	Solvent Extraction	Mechanical Extraction
Oil Recovery	High (up to 99%)	Lower than solvent extraction
Efficiency	More efficient for high-oil content seeds	Less efficient for high-oil content seeds
Cost	Higher initial investment	Lower initial investment
Use in the US	Widely used	Not widely used due to low oil recovery

Solvent extraction is favored for its high oil recovery rates, making it economically viable for large-scale operations.
Mechanical extraction, while less efficient in oil recovery, is sometimes preferred for producing specialty oils or in settings where solvent use is restricted.