The processing of vegetable oil in commercial applications is commonly done by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derived hexane. This technique is used for most of the "newer" industrial oils such as soybean and corn oils.
How is edible oil processed?
In the processing of edible oils, the oil is heated under vacuum to near the smoke point or to about 232 °C (450 °F), and water is introduced at the bottom of the oil. The water immediately is converted to steam, which bubbles through the oil, carrying with it any chemicals which are water-soluble.
What is a Ghani oil press?
A ghani is a traditional Indian oil press, driven by a horse or ox.