What is an Essential Oil?

Essential oils are volatile fragrant compounds obtained from plants through the process of extraction. Plant materials from seeds, roots, flowers, leaves, stems, bark, and resin can be used to extract the essential oil of the plant. Extraction can be done with fresh or dried plant material.

 

Only Nature Can Produce Essential Oils

  • Plants contain 0.01 – 10% essential oil content, but the average amount found in most plants is 1 – 2%.
  • The number of plants that actually give up their essential oil through extraction is relatively low.
  • The amount of essential oil that can be collected from the plant through extraction varies, and, as a result, directly impacts the price.
  • Lower yield and availability of the plant drives the price of the essential oil upwards.

To be Most Effective, Essential Oils Must be 100% Pure and Natural.

What Does This Mean?

  • The oil does not contain any synthetic component, adulterant, or “nature identical” ingredients.
  • The oil is not cut with a less expensive oil or diluent to bring down the cost and quality.
  • The oil has not been reconstructed in a laboratory.
 
 

Methods Of Extraction

Steam Distillation

The most widely used method of obtaining essential oils from plants.
Typical yield is 1-2% by weight of the essential oils on distillation, but some oils are substantially less (for example, rose oil yield can be as low as 0.015%, and this drives the cost of the essential oil).

Process:

  1. Plant material is placed into the vessel (container).
  2. The vessel is closed.
  3. A combination of steam and essential oil vapors go out of the vessel.
  4. The steam is cooled and condensed.
  5. The oil separates from the water due to the differing densities.
  6. The essential oil is collected.
  7. The water is recycled for the next distillation, or it is collected for use as floral water since it has smaller amounts of essential oil trapped within it.

Example: Lavender oil

 

Cold-Pressed/Expression

The most common method of extraction of citrus oils from the peel of the fruit.

Process:

  1. The peel of the fruit is scored.
  2. The peel is pressed.
  3. The essential oil is collected and filtered (may be centrifuged to remove water as well).

Example: Mandarin oil
Note: For many citrus fruits, the essential oil is a co-product of the juice production whereby the fruit is used to make juice and the peel is used to make the essential oil. Many citrus essential oils are also used for the flavor industry.

 

Maceration

Yields a product with lower essential oil content.

Process:

  1. The plant material is soaked in a plant oil or alcohol solvent
  2. The solvent pulls out the volatile essential oil components.
  3. The plant material is filtered from the liquid.
  4. The plant oil/alcohol liquid that has trapped the essential oils inside it is used for flavor and fragrance materials.

Example: Vanilla extract
Note: For the production of vanilla extract, there is an elaborate curing process for drying the vanilla beans before this extraction.

 

Solvent Extraction

  • Produces highly concentrated extracts, known as an absolute, concrete, resin, or pomade.
  • Solvent extraction is performed on plant materials whose volatile components would be damaged, changed, or not given off via steam distillation.
  • This process is run at room temperature without the presence of additional heating of the plant material.

Process:

  1. The plant material is loaded into the vessel.
  2. The solvent is added to the vessel (or plant material is dipped into a solvent for a set amount of time).
  3. Solvent absorbs the essential oils, plant waxes, fats, and cellulosic material from the plant.
  4. The solvent is removed under vacuum from the plant/solvent mixture.
  5. The concrete remains, which contains the waxes and essential oils from the plant.
  6. The concrete is washed with alcohol.
  7. The alcohol is driven off under vacuum.
  8. The product is filtered.
  9. The final product is the absolute.

Example: Jasmine absolute

 

Supercritical Extraction / CO2 Extraction

  • The method uses carbon dioxide under pressure to extract the volatile components of the plant.
  • An extremely expensive process, but also yields very concentrated extracts.
  • The process has the most success using dried plant materials or concretes as starting materials.

Process:

  1. Dried plant material or concrete is loaded into a vessel.
  2. CO2 is administered under various constant temperatures and high pressures.
  3. The final product is a CO2 extract.
  4. The solvent is removed under vacuum from the plant/solvent mixture.

Example: Ginger CO2 extract
Note: This method is mostly done on spice materials, vanilla, and concretes of floral materials.

 

Enfleurage

  • A process that is a form of solvent extraction using animal or plant fats/oils.
  • Usually, this process is done with fresh flowers from the plant.
  • This process was developed by ancient Egyptians and is one of the earliest forms of plant extractions for cosmetics.

Process:

  1. Glass trays are covered by animal or plant fat/oils.
  2. Fresh flowers are placed on the trays.
  3. The trays are left for several days/weeks in order for the fat/oil to absorb the essential oil from the flowers.
  4. Fresh flowers are replaced several times on the trays, so the fats/oils can absorb more of the essential oil from the plant.
  5. The flowers are removed from the trays.
  6. The fat/oil materials are solubilized in alcohol.
  7. The alcohol is evaporated off.
  8. The final product is the floral enfleurage.

Example: Jasmine Enfleurage
Note: This process usually yields a weaker product compared to absolutes because the solvents used to produce the absolutes are stronger than the plant oil/fats. Therefore, the solvent pulls more essential oil from the plants than the animal fat/plant oils.