Methods of Extraction for Vegetable (Carrier) Oils
Cold Pressed or Cold Expeller Pressed:
Cold pressed oils, also known as cold expeller pressed oils, have been mechanically pressed from the fatty portions of the botanical while ensuring that the maximum temperature (caused by friction) does not exceed 120 degrees.
Expeller pressed oils are mechanically pressed from the botanical material at high pressure to obtain maximum yield. Not all expeller pressed oils are cold pressed as high pressure extraction can cause temperatures to rise above 120 degrees. Only if temperature is monitored and kept under 120 degrees, can the oil be called cold pressed. Otherwise it is simply called expeller pressed. FromNatureWithLove.com always strives to supply cold pressed oils whenever possible, however, some oils cannot be cold pressed.
Sometimes it is necessary to use a solvent in order to extract the oil from certain seeds, nuts or kernels in order to make the extraction cost effective. Once the oil has been obtained, the solvent is then removed from the oil, but a trace percentage of the solvent may still be present in the final oil. Coconut, Palm, Grapeseed and Rice Bran are typically solvent extracted.
CO2 extracted oils are extracted using fluid carbon dioxide as the solvent. Carbon dioxide is converted to liquid using high pressure making it a safe and effective solvent that allows all the desirable active constituents of a plant to be collected without the risk of heat degradation. Once the extraction is complete, the pressure is released allowing the carbon dioxide to return to its natural gaseous state, leaving behind only the extracted essence of the plant. CO2 extracted oils are the closest representation of the natural plant ever achieved. CO2 total extracts include the volatile components as well as the heavier, waxy components that give plants their color, and are therefore thick and waxy in consistency.
An infused or macerated oil is a vegetable oil that has been "infused" with the fat soluble properties of other botanicals. Plant material is bruised and soaked in a base oil for a set duration of time. The base oil is sometimes gently heated to encourage infusion. The material is then filtered. Additional material may be infused in the same oil a number of times. The final oil is then well filtered to remove any traces of plant particles. The benefit to using an infused vegetable oil is that the infused oil will contain the therapeutic properties of both the vegetable oil and the botanicals that were infused into the oil.
RBD is the abbreviation for "Refined, Bleached and Deodorized." Within the description / extraction method for each of our vegetable oils, we note those oils that are refined, bleached or deodorized.
Some oils undergo a refinement process in order to remove impurities, improve the color or texture, or stabilize the shelf life of the oil. The oil is reacted with a weak base solution to saponify the free fatty acids into soap. The oil is then centrifuged and washed with water until the pure oil remains. The oil may also be degummed to remove the sticky phospholipids, color pigments and odor lending portions.
Some lipids are bleached in order to improve the color and clarity of the oil. Bleaching is generally done by passing the oil through fuller's earth or clay and then filtering the oil.
Some lipids undergo a deodorization process in order to remove compounds that lend an unappealing or overpowering aroma to the oil. This is generally done by blowing high temperature steam through the oil to vaporize the aromatic components. This process is made more effective by heating the oil to high temperatures and performing this process under a vacuum to help remove all of the volatile odorous substances. Due to the high temperatures used, deodorization is clearly the most damaging process of refinement.
Oils that are winterized are cooled and filtered to remove the solid crystallized fractions. This process results in a lighter, clearer oil.