Methods of extraction 

Steam Distillation

This is the most commonly used method. The raw materials are collected and placed in large vats with water and then heated. The steam extracts the oil from the plant and the vapour produced passes into a condenser and is then cooled with the essential oil separating from the flower water.  

Expression

This method is used for citrus oils such as lemon, lime, mandarin, orange and bergamot and the essential oil is expressed by squeezing them from the rind or peel of the fruit. This method is referred to as the cold press method and the best source of raw material would be organically grown fruit, which has not been sprayed with pesticides.

Solvent extraction

The raw materials are covered by a solvent such as ether, benzene, petroleum, hexane or acetone and then heated to extract the essential oil. This is then filtered which leaves a paste called concrete made up of wax and fragrance which is then mixed with alcohol and distilled at low temperatures, the alcohol absorbs the fragrance and when the alcohol is evaporated off an aromatic absolute remains. This method is used on delicate flowers such as rose and jasmine and as many tonnes of the flowers are needed and it is a relatively time consuming process making the oils extracted by this method more expensive than others.

Enfleurage

This is one of the earliest methods used to extract essential oils from flowers. A pure, odourless, cold fat is placed in a thin layer on a glass frame and the flower petals are placed in layers on top. After 30 hours the fat will have absorbed the essential oils. The glass frame is turned and new flowers take their place. Once the fat is saturated with the essential oils it, is washed with alcohol, which absorbs the essential oils and finally the alcohol is evaporated off leaving pure essential oil. This is an expensive method of extraction, which is not in common use.

Maceration

The flowers or petals are slightly ruptured and placed in warm fat. This is repeated many times until the fat becomes saturated with essential oil and is then bathed in alcohol, which evaporates leaving essential oil.

Phytonic process

This is a new highly efficient method of solvent extraction developed in 1994 by Dr Peter Wilde. The solvent used is fluorocarbon which is injected into a sealed unit with the plant material using low pressure. A liquid gas forms which is then released into another sealed chamber where it evaporates and produces phytols.