Crab oil doesn't come from crabs; it is the name for an oil extracted from the nuts of the Andiroba tree. Andiroba trees are common in South America. Crab oil is also known as Andiroba oil and has been used for centuries for its health benefits. Crab oil is extracted by boiling, hand pressing, and expeller pressing.
Extraction by Boiling
In the boiling extraction method, Andiroba nuts are first shelled. Then, they are boiled in water until they begin to come apart. Salt is often added to aid in this process. As the nuts break, the oil floats to the surface of the water. Once the water cools, the crab oil is skimmed from the water's surface.
Extraction by Hand Press
In the hand press extraction method, Andiroba nuts are first ground to a pulp. The pulp is then placed between two hard surfaces and pressed by hand. This removes the pulp's moisture, which contains both oil and water. This oil and water mixture is collected. Once the liquid settles, the oil floats to the surface and is collected.
Extraction by Expeller Press
In the expeller press extraction method, a simple machine called an expeller press is used to force the Andiroba nuts through an open cavity. Inside the cavity, the nuts are subjected to friction and pressure. As the cavity narrows, only moisture is able to pass through. Ultimately, the oil emerges from the expeller press and the dry parts of the nut are left behind. Expeller pressing also generates heat due to friction which helps separate crab seed oil from the Andiroba nut.