Extraction Methods for Essential Oil
Essential Oils are made from a process called Extraction.
There are several different methods of Extraction and in this video, we will cover 3 of them.
Steam Distillation
Steam Distillation is the most popular method used to extract and isolate essential oils from plants for use in natural products. This happens when the steam vaporises the plant material’s volatile compounds, which eventually go through a condensation and collection process.
Steam Distillation Process
- A large container called a Still, which is usually made of stainless steel, containing the plant material has steam added to it.
- Through an inlet, steam is injected through the plant material containing the desired oils, releasing the plant’s aromatic molecules and turning them into vapour.
- The vaporized plant compounds travel to the condensation flask or the Condenser. Here, two separate pipes make it possible for hot water to exit and for cold water to enter the Condenser. This makes the vapour cool back into liquid form.
- The aromatic liquid by-product drops from the Condenser and collects inside a receptacle underneath it, which is called a Separator. Because water and oil do not mix, the essential oil floats on top of the water. From here, it is siphoned off. (Some essential oils are heavier than water, such as clove essential oil, so they are found at the bottom of the Separator.)
Cold Compression
This method is also called Cold Press, Expression or Scarification and it is used specifically for citrus peels.
Cold Press Process
- The whole fruit is placed in a device that mechanically pierces it to rupture the essential oil sacs, which are located on the underside of the rind. The essential oil and pigments run down into the device’s collection area.
- The whole fruit is pressed to squeeze out the juice and the oil.
- The oil and juice that are produced still contain solids from the fruits, such as the peel, and must be centrifuged to filter the solids from the liquids.
- The oil separates from the juice layer and is siphoned off into another receptacle.
C02 Extraction
C02 is colourless, and odourless, and can be easily and completely removed by releasing the pressure in the extraction chamber.
This absence of potentially harmful solvents in C02 extraction means neither the human body nor the environment is polluted.
C02 Extraction Process
- Pressurised carbon dioxide becomes liquid while remaining in a gaseous state, which means it is now “supercritical.” In this state, it is pumped into a chamber filled with plant matter.
- Because of the liquid properties of the gas, CO2 functions as a solvent on the natural plant matter, pulling the oils and other substances such as pigment and resin from the plant matter. 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.
To learn more about essential oils make sure you check out our other videos.
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Sources:
https://www.newdirectionsaromatics.com/blog/articles/how-essential-oils-are-made.html
