Essential oils, definitions and production methods

The origins of essential oils

Thanks to the long process of evolution and the resulting selection, plants have been able to adapt to defend themselves and resist different environmental conditions. Some have undergone morphological transformations, while others have been able to evolve their metabolism to the point of developing molecules of interest for various functions, such as insect control, reproduction or even communication. It is from this last large group of aromatic plants that we now derive essential oils.

Definitions

Essential oils are fragrant products, generally complex in composition, obtained from a botanically defined plant raw material, either by steam distillation, dry distillation or by a suitable mechanical process without heating.

Production methods for essential oils

Essential oils can be obtained in 4 different ways:

• The steam distillation Water vapour passes through the plant to extract volatile compounds. This process is suitable for almost all types of plants or parts of plants. (Essential oils of Lavender, Lavandin, Camomile, Immortelle, Geranium, Eucalyptus, etc.).
• L'hydrodistillation Steam distillation: This involves steam distillation while the plant remains immersed in water. It involves more hydrolysis than steam distillation but is suitable for all products, even the most difficult to extract. (Rose, Frankincense and Myrrh essential oils)
• Cold expression This is a mechanical process that does not involve hydrolysis. It extracts volatile molecules but also non-volatile ones. It is reserved for citrus epicarp.
• The dry distillation :  This technique, which involves pyrolysis of the wood, is used specifically for softwoods.

While the extraction method is clearly defined according to the essential oil to be extracted, the quality and traceability criteria are many and varied. It's not always easy for those involved in the industry, or for consumers, to find their way around. Organic certification is the best known and most important in the sector. But what guarantee does a certified organic essential oil offer?

Find out more in our next article Organic certification for essential oils.