Essential oils are extracted in several different ways. Below are the most common methods of essential oil extraction.
The most common method of extracting essential oils from the plant is steam distillation. Fresh or dried plant material is put into a still and a pressurised steam is generated and circulated through the plant material.
The essential oils are released from the heat of the steam which opens the specialised cells or glands. The essential oil that is released travels with the steam molecules through a tube into the still’s condensation chamber.
As it cools it condenses into oil and water the essential oil naturally separates from the water.
With this method the peel of a fruit grated while rolling over a trough. The tiny specialised cells containing the essential oils is punctured.
The fruit is then pressed to squeeze the juice and the essential oil from the pump. The essential oil rises to the surface of the juice and is then separated by a centrifuge.
This method is used for delicate flowers that would simply dissolve in the heat of distillation.
A solvent compound is poured over the petals and buds and the essential oil dissolves itself into the solvent.
Solvents vary from the new a method of using carbon dioxide or the environmentally hazardous liquid butane, to crude alcohol, or even more toxic chemicals such as ether, hexane, benzene or other petroleum-based compounds.
This method involves tapping shrubs or trees to extract the resin from them. Tapping is making a hole far enough into the trunk to puncture the vacuoles, this allows the sap to exit the tree.
The tree is then left to repair its damage by filling the wound with resin. This takes a few days, after that the excess resin is collected.
There are several other extraction methods however steam distillation, cold pressing and solvent extraction are the most common methods.
If you’d like to find out more about essential oil you may enjoy The Essential Oil Maker’s Handbook which covers extracting, distilling and enjoying plant essences.