Essential Oil Extraction Methods

Essential oils are the essence or “soul” of a plant – its quintessence – offering both healing and pleasure when inhaled or used on the skin. How are they made?

Essential oils have chemical constituents that are proven to interact on a cellular level for human health and healing.  They are extracted through a variety of methods that in effect “de-emulsify” its components, separating the water and oils from the plant matter.

The most common method to extract essential oils is steam distillation, but there are other methods like cold pressing (mainly used for citrus fruit rinds) and C02 extraction. Other infused oils include enfleurage, which are aromatic oils, not essential oils.

Read more about the various methods for both essential oil and aromatic oil extraction, below.

Methods of Extraction

Steam Distillation 

The most common method for essential oil extraction is steam distillation. Plant matter is placed in a large container (still) and steam is injected, causing the plant to release its oils in a vaporized state. They travel through a condensation flask/condenser, and two pipes separate the hot water, which exits, and the cold water enters the condenser, where the vapor cools back into liquid form. 

Because water and oil do not mix, the essential oil can be siphoned from the water. The water left behind in this process is the hydrosol or “floral water”.

C02 Extraction

In CO2 extraction, none of the constituents of the oil are damaged by heat and thus offer a higher quality oil that is truer to the plant’s original state. Instead of heated water or steam, CO2 is used at temperatures between 95 to 100 degrees F.  Pressurized carbon dioxide acts as a solvent and is pumped into a chamber filled with plant matter, pulling the oils and other substances such as pigment and resin. The essential oil content then dissolves into the liquid CO2. The CO2 is brought back to natural pressure and evaporates back into its gaseous state, while what is left is the resulting oil.

Cold Press Extraction

Used for citrus fruits like orange, lemon, grapefruit and lime, the whole fruit is pressed to squeeze out both juice and oil, and the liquid is centrifuged to filter the solids and liquids. The oil separates from the juice and is captured as the fruit’s essential oil.

Maceration/Infusions

This is an easy, at-home way to create oils with essential oil benefits. Using entirely dried out plant matter (to avoid spoilage), crush or grind into a course powder and add to a carrier oil such as wheatgerm or other vegetable oil. Add a solvent of your choosing and allow to sit for a week, shaking occasionally. Strain and use the oil for massage or as part of recipes.

Enfleurage

A traditional and now rare method is to press flowers into fat (animal or vegetable), replacing frequently with fresh petals, and over several weeks or even months the fat becomes infused with the flower’s fragrance compounds, called an “enfleurage pomade”. The pomade is washed with alcohol to separate the botanical extract from the remaining fat, which can then be used as an ingredient in soap or perfumery. Enfleurage is not an essential oil but rather a scented oil, and is used for aromatic pleasure but not holistic aromatherapy. 

Solvent Extraction

Food grade solvents like hexane and ethanol are used to isolate essential oils from plant material. Usually used with plants that yield low amounts of essential oil, that are largely resinous, or that are delicate aromatics unable to withstand the pressure and distress of steam distillation. This method produces a finer fragrance than any type of distillation method, and is typically used in perfumery rather than aromatherapy, as the chemical solvents do not preserve the naturally healing benefits of the plant. This is mostly used for sturdy plants, like roots, resins and woods.

Water Distillation

Submerge fragile plant material in pure boiling water and allow to cool, whereby the oils and water separate into essential oil and floral water/hydrosol. This is mostly used for delicate flowers such as roses and orange blossoms. 

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Quality oils come from quality distillers and producers, as the process of extraction is as important as the raw material for getting a quality final product. Be sure to purchase from reputable sellers to ensure you are getting authentic and pure essential and aromatic oils.