The method of extracting aromatic substances were developed by alchemists in the early civilisations of the Middle East and ancient Egypt.
The philosophy of the alchemists was, that the spark of divinity could be discovered in matter. By subjecting botanical and mineral substances to heating in water baths and stills, the divine eternal spirit would be extracted. While they did not succeed in extracting the divine eternal spirit, we must be grateful for the practitioners of alchemy, for what we know of essential oil extraction today.
How are essential oils are extracted?
The method used to produce an essential oil depends on the type of plant material that the oil is being extracted from.
A plant’s essential oils are contained in tiny sacs. This can be found on the surface of a leaf or flower. Sometimes you can find it in the bark, seeds or roots of a plant. Producing essential oils involves one of several methods to burst open the sacs and collect the oil. For example if you rub leaves of a herb or a piece of peel from a citrus fruit in your hands, it will break the vessels to release the oil and you can smell the fragrance.
Most essential oils are produced by a process of steam distillation. However the oil in some flowers and plants is extremely delicate and would be destroyed by the heat used in this method. For example our rose essential oil and myrrh essential oil is obtained by solvent extraction.
The type of plant material determines which method of extraction is used to produce the essential oil.
What are the processes of essential oil extraction?
Steam distillation of essential oils
Steam distillation is the most popular method for extracting essential oils. Herbs, roots, bark and resins are used in this process.
Cold pressing of essential oils
The simplest way to extract an essential oil is to press the plant material and then collect the oil. This method is used when the essential oils are found in the outer rind of a fruit and are easily released, as is the case with citrus peel. Citrus fruits, such as grapefruit, orange, lemon are mechanically pressed to extract their liquid, and then the watery juice is separated from the essential oil.
Solvent extraction of essential oils
This method is used for plants whose essential oils would be degraded by distillation. This is a very gentle process which tends to create less ‘rearrangement’ of the essential oil compounds, compared with distillation methods.