Aromatherapy - Introduction - How Are Essential Oils Extracted

How Are Essential Oils Extracted?

There are many ways of extracting essential oils from plants. Essential oils are highly concentrated extracts and should not be confused with infused oils, tinctures and infusions that draw only some of the components from the plant.

Essential oils can be produced by: steam distillation, cold pressing, solvent extraction or hyperbaric extraction. Each extraction method has its strengths and weaknesses. Characteristics and quality of the oil varies depending on the method used.

Steam Distillation

The most common form of extraction is steam distillation as it yields the most pure form of the oil. The plant material is placed on screens and steam is allowed to pass through, drawing out the main components of the plant. The essential oil laced steam is condensed, leaving only distilled water and essential oil. This mixture of water and oil is collected and stored in a large vat. The heavier distilled water sinks to the bottom of the vat, leaving the essential oils to rise to the surface. The oils are then drawn off and carefully bottled.

Cold Pressing

This method is commonly used in the production of oils taken from citrus rinds, including the rinds of: lemons, oranges, grapefruits, tangerines, bergamots and mandarins. The rinds are chopped up, ground and then pressed. Pressing forces the essential oil components in the citrus rind together and this process produces a mixture of water and essential oils. The mixture is then left to settle so that the essential oils can be separated for bottling. This method gives the essential oils a more fragile property than from any other method and prevents them from lasting much more than one year.

Hyperbaric Production

This method uses a combination of extremely high pressure and carbon dioxide gas to extract the essential oils from the plant. The high pressure causes the carbon dioxide to liquefy and mix with the essential oils from the plant material. The gas is then separated from the essential oil. This is an expensive method to use but is ideal for extracting lighter oils such as Jasmine.

Solvent Extraction

This method is not favoured by aromatherapy advocates as it requires the use of harsh solvents. The solvents evaporate once the essential oils become successfully extracted, yet some solvent residue is left in the oil. Essential oils extracted by this method are known as absolutes.