The essential oil company
The Essential Oil Company
8225 SE 7th Ave, Portland, OR, 97202
800-729-5912
www.achs.edu
Essential Oil Extraction
The Essential Oil Company
8225 SE 7th Ave
Portland, Oregon 97202
503-872-8772
http://www.essentialoil.com 
Essential oils are volatile liquids that reside in many plants. They can be found in varying parts of different plants. Some oils, such as Rose Oil (Otto, Attar) are found in the flower petals. Some oils such as Vetivert Oil are found in the roots of the plant.
The orange tree can produce three very distinct essential oils (as will most citrus trees); the flower produces “Neroli Oil”, the leaf produces “Petitgrain oil” and the peel (exocarp of the fruit) produces Orange Oil.
The needles of various species of conifers produces an essential oil that quite different than that distilled from the wood. Sometimes seeds are distilled for their essential oils, such as Anise seed, Cardamom and Fennel seeds.
Methods for Extracting Essential Oils
Methods for extracting the essential oil, varies from plant to plant and material to material.
One of the earliest methods for capturing the essential oils from plants is Maceration. Maceration is “warm” fat extraction, where the fixed oil (such as olive oil) serves as a solvent for extracting the essential oil from plant material. This of course does not isolate the essential oil, but rather the essential oils remain as fragrant components of a scented oil. This is how the Holy Anointing Oil of the Bible was made.
Then, there is Enfleurage. Enfleurage is a cold fat extraction, where delicate flower petals, such as rose and orange blossoms are allowed to sit for a period of time on top of a layer of de-odorized lard. The process of laying flower petals on the fat, then removing the petals is repeated periodically for several weeks. The fat is then “washed” with alcohol, to remove the aromatic components. The alcohol can then be evaporated to yield an aromatic product.
Next, there is Solvent Extraction. This method is used for Jasmine for example, because Jasmine flowers will not yield an essential oil to distillation.
Solvent extraction, is allowing your raw material to sit in a “bath” of solvent, such as hexane. The first extraction using a solvent yields a “concrete”. A concrete contains waxes and aromatic materials from the flower petals. The concrete is then “washed” with alcohol to remove most of the aromatic components. The resulting product is called an “Absolute”.
Another method of extraction is “Expression”. Expression is used to extract essential oils from citrus fruits. Essential oils of Oranges (bitter and sweet) and Lemons is a bi-product of the juicing process. Whole fruits are pressed with a great deal of pressure. The result is a mixture of juice, peels and essential oils. The liquid mixture is placed in a series of centrifuges. This separates the components of the liquid by specific gravity. Oil of Lime however is generally distilled from the peel.
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Distillation
Essential oils are volatile liquids. When the temperature is at the correct level, they will evaporate. If captured, the resulting gasses can then be cooled down and will subsequently revert back to a liquid state.
There are different types of distillation, which can be employed for differing conditions and types of plant material.
Hydrodistillation
Hydrodistillation, is when the plant material being distilled is free floating in water, with the water being heated by an external source. The external source can be a flame, hotplate, steam jacket or water bath. This method is used for delicate flowers such as Rose Petals and Neroli (Orange Blossom) Flowers. Almost anything else can be distilled in this manner. When heated directly by a flame or hotplate, there is a risk of burning the raw material, thereby tainting the product. Steam jackets and the Bain Marie (water bath) will keep the distiller from burning the raw material, because the temperature never rises above the boiling point of water.
Water/Steam Distillation
Water/Steam distillation is where the material being distilled is in the same container as the water being boiled. The plant doesn’t touch the water. The steam from the boiling water passes through the plant material, releasing the essential oils.
As with all forms of essential oil distillation, the steam carries the essential oils in a suspension. That is to say that the essential oils remain separate for the most part from the water. There is also a difference between the specific gravity of the essential oil and that of water. With water generally having a higher specific gravity. If this is the case, then once condensed, the oils will float on top of the water. If the specific gravity is higher than that of water, the value of 1.0, then the essential oils will sink below the water. This is the case for essential oils such as Wintergreen, Cinnamon and Allspice.
Water/Steam distillation can be used with most plant materials. It is slow process, but will yield a very nice product.
Steam Distillation
Steam distillation is when steam is produce externally by a boiler, then introduced into a container holding raw material. This is the process generally used in commercial operations where large quantities of raw material have to be distilled during a relatively short period of time. The steam, which is introduced, is done so under pressure. The wet steam accelerates the distillation process.
Robert Seidel, Portland, Oregan
