essential oil extraction

 

Essential oils are natural aromatic extracts from plant material including grasses, leaves, flowers, needles, twigs, peels of fruit, seeds, bark and roots.  For example, in roses essential oils are found in the flowers, in basil it is in the leaves, in sandalwood in the wood, frankincense in the resin of its tree, and so on.

The aromatic essential oil compounds are stored in tiny pockets in plant material and must be released. The type of plant material (leaves, flowers, roots) being used determines which method of extraction will produce the best results.

 

METHODS OF EXTRACTION

 

Distillation

Steam distillation is the most popular method to extract essential oils.

During this process the botanicals are placed in a still and pressurized steam is forced through the plant material. The hot steam forces open pockets aromatic compounds. The compounds escape from the plant material and evaporate into the steam.

The steam must be hot enough to allow the release of the essential oil while not damaging the plant material The steam with essential oil then passes through a cooling system where the steam condenses into a liquid consisting of essential oil and water. The essential oil, being lighter than the water, will float to the top and can then be separated from the water. The water by-product of distillation is called a floral water.

 

Expression

Expression is called a "cold pressed" method of extraction since no heat is needed to extract the essential oil. It is mostly used to extract citrus essential oils. In this process, the oil is forced from the material under high mechanical pressure. Many base oils are extracted in the same way.

 

Solvent Extraction:

Some plant materials, like jasmine flowers, rose petals and linden blossom, are too delicate to survive the process of distillation. To extract their aromatic essence a process called solvent extraction is used. This process utilizes petroleum solvents such as petroleum ether, hexane or toluene; alcohol solvents such as methanol or ethanol; or carbon dioxide. As the solvent is added to the botanical it is absorbed and allows the release the aromatic compounds. 

These solvent extracted compounds are called "absolutes" and are very concentrated.  Technically they should not be called essential oils.

Petroleum Solvent:  Years ago almost all essential were extracted in this manner. However, since residues of the petroleum solvent may remain in the essential oil, solvent extraction was not recommended for essential oils used for aromatherapy. These residues may also cause allergic reactions and skin irritation.

Ethanol Solvent: While the petroleum solvents can be very dangerous, ethanol (food grade drinking alcohol) is a rather benign solvent.

Carbon Dioxide: Carbon dioxide extraction is a fairly new way to extract essential oils from botanical material. It produces great essential oils but at this time is also very expensive. Under pressure the temperature of the carbon dioxide is increased to about 92 degrees Fahrenheit (33 degrees Celsius). At this temperature carbon dioxide enters a phase that is part liquid and part gas. Carbon Dioxide is an excellent solvent to extract pure essential oils since carbon dioxide does not chemically interact with the essential oil extracted. To remove the carbon dioxide solvent, simply decrease the pressure and the carbon dioxide returns to a gaseous state leaving the pure essential oil with no residues.

 

The most important consideration when purchasing essential oils is to buy from a reputable supplier that lists the method of extraction and tests their oils for the presence of adulterated additives.


The essential oils used in Chagrin Valley products are steam distilled
except for the citrus oils which are cold pressed.
If we use any absolutes they are either Carbon Dioxide extracted (if available)
or Ethanol extracted.