Another expression method of extracting essential oils is coldpressed expression, or scarification method. It is used to obtain citrus fruit oils such as bergamot, grapefruit, lemon, lime, mandarin, orange, and tangerine oils. In this process, fruit rolls over a trough with sharp projections that penetrate the peel. This pierces the tiny pouches containing the essential oil. Then the whole fruit is pressed to squeeze the juice from the pulp and to release the essential oil from the pouches. The essential oil rises to the surface of the juice and is separated from the juice by centrifugation.
It is important to note that oils extracted using this method have a relatively short shelf life, so make or purchase only what you will be using within the next six months.
Although many citrus oils are also produced by steam distillation, they seem to lack the vibrancy of the cold pressed oils.