Essential oils are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, sfumatura, absolute oil extraction, resin tapping, wax embedding, and cold pressing.

What are the main ingredients in essential oils?

Essential oils (EO) are complex aromatic substances derived from plants that are mainly composed of terpenes and other compounds, namely aldehydes, fatty acids, phenols, ketones, esters, alcohols, nitrogen and sulphur compounds (reviewed by Ippolito et al., 2005).

Where do essential oils come from?

Essential oils come from various species of flowers, grasses, fruits, leaves and trees. They are found in the secretory system of plants (in other words, the bark, seeds, leaves, petals, stems and roots). On average, essential oils are 80 times more potent than the dried form of the herb.