Mustard oil can mean either the pressed oil used for cooking or a pungent essential oil, also known as volatile oil, of the mustard plant. The essential oil results from grinding mustard seed, mixing the grounds with water, and isolating the resulting volatile oil by distillation. It can also be produced by dry distillation of the seed. Pressed mustard oil is used as cooking oil in some cultures; however, sale is restricted in some countries due to high levels of erucic acid. Variations of mustard seeds low in erucic acid have been cultivated at times.
