The extraction process is a factor in determining the purity of the oil. Before purchasing carrier and essential oils, it is important to become knowledgeable of these methods.
Steam from boiling water is used to extract the essential oil from the plant material. The stream rises and passes through a cold coil, turning into a liquid. The essential oils floats on top of the water and is skimmed off. The leftover water contains water-soluble components and is used as floral water. Steam distillation is extensively used and produced a good quality essential oil.
Carbon Dioxide Gas Extraction
Expensive high-technology equipment is used to extract the essential oils. It employs carbon dioxide gas (CO2), high pressure, and low temperature. This process produces an oil that retains a greater amount of aromatic components than oil derived by steam distillation. The scent of CO2 extracted oil is more identical to that of the original plant.
There are two types of CO2 extractions: Select and Total.
Select CO2 Extraction
In the select method, the oil is extracted at a temperature of around 88F (31C). The plant material is placed in a chamber and then the compressed CO2 gas is released. As the gas passes through the plant material, it draws the plant components into solution. When the process is completed the pressure is lowered, and the extracted materials precipitate out and are collected. The CO2 gas is then recompressed and recycled to be used again, without leaving any residue in the extracted oil. The extracted oil contains selected components similar to oils that are steam distilled.
Total CO2 Extraction
In the total method, the plant material is processed at a higher temperature. The extracted oil contains more plant material than the select method.
Cold Pressed Cutrus Oils
The essential oil is produced from the citrus peel. The fruits are placed on a conveyor belt and then dropped into a cup with knives. As the cup closes, the knives puncture the fruit. The fruit is pressed for juices, and then the peel is sprayed with water to create a slurry, which is collected and put through a centrifuge process to separate out the essential oil.
Flowers, such as rose and jasmine, are soaked in hot oil to release their fragrant components into the oil.