Which method of oil extraction uses pressure to release the oil?

The method of oil extraction that uses pressure to release the oil is expression. This technique involves mechanically squeezing or pressing plant materials to extract essential oils. It is commonly employed for citrus oils, where the peels are pressed to release oil. The process relies solely on physical pressure, ensuring that the oil extracted is of high quality and retains its aromatic properties, as there are no additional solvents or heat involved.

Cold pressing is indeed a similar method, particularly for citrus fruits, and could also be seen as a subset of expression. While both techniques can be associated with extracting oil without the use of solvents or significant heat, the term "expression" encompasses a broader range of methods beyond just cold pressing and focuses specifically on the application of pressure.