What is the main method used to extract essential oils?

The main method used to extract essential oils is distillation. This process typically involves steaming plant materials, which allows the volatile compounds, including essential oils, to evaporate. The steam then passes through a condenser, where it cools down and returns to a liquid state, separating the essential oils from the plant material. Distillation is favored because it effectively preserves the aromatic properties and therapeutic qualities of the oils without the use of chemicals, making it a preferred technique in the production of high-quality essential oils.

In contrast, fermentation is a biological process primarily used in food and beverage production rather than for extracting essential oils. Expression is a method commonly associated with citrus fruits, where oils are physically squeezed from the rind, but it is not as universally applicable as distillation. Sublimation involves the transition of a substance from solid to gas without passing through a liquid state, which is not suitable for extracting essential oils from plant materials, as the oils do not exist as solids.