Essential oils are the volatile substances produced by plants that have been extracted through a distillation process. They are not essential for the plant’s survival. Plants synthesize volatile substances along secondary metabolic biochemical pathways. This means that the plant does not metabolize them in order to continue living.
Essential oils are the essence of the plant, meaning that they contain within it the unique characteristics of that plant. It is a sort of blueprint that consists of the many chemical constituents found within the plant. Essential oils are volatile substances that evaporate easily and do not leave an oily residue. They are very different than base oil made typically from nuts and seeds. The base oils do leave an oily residue and do not evaporate.
Paracelsus, an alchemist who lived from 1493 to 1541, said that the essence of a plant is the very spirit of the plant. In alchemy, the spirit of the plant contains the personality, or unique chemical structure, or signature, of the plant.
Scientific and historical definitions of the term ‘essential oil’ are very similar while remaining quite different. Modern day science does not typically consider the spirit of a living organism as medieval alchemists did. However, the consideration that the essential oils are unique chemical blueprints of an organism echoes the alchemist theory that essential oils contain with it the personality of the plant.