Carrier Oils: Extraction Methods
Cold-pressing: In cold-pressing or cold-extraction, the nuts or seeds of a plant are placed in an expeller and are crushed or pressed to release their oil. Temperatures are kept at a minimum (below 80 deg. F) NOTE: Unless the oil's label indicates that it has been expelled, expressed, cold-pressed or is 'virgin', assume that is has gone through a heat, solvent or other refining process. Keep in mind that United States regulations on cooking oils are not as strict as those in Europe.
Hot-Extraction: Hot (or heat)-extraction is used in large-scale production because it yields more oil than cold-pressing does. However, the vitamins and fatty acids found in oils are destroyed by excessive heat. Unsaturated fatty acids are especially sensitive to high temperatures. These oils are commonly sold as cooking oils and are not suitable for use in skin care as they lack therapeutic benefits.
Solvent-Extraction: Solvent-extraction is used to get every amount of oil possible from the seeds and nuts. Hexane (which is derived from petroleum) and other toxic chemicals are used. This method is less costly and yields a greater amount of oil. However, residues are still left over in the oil making them unsuitable for use in skincare, and for eating.
Distillation: Some oils are difficult to extract and are therefore put through a distillation process. Essential oils are commonly extracted using this method, as are some carrier oils. A common method is steam-distillation where water is heated to produce water vapor, which carries with it the volatile, aromatic chemicals from the plant. The water vapor condenses and the essential oil is collected.
Refined (RBD): A large percentage of carrier and cooking oils are refined after being pressed or extracted. This process may include degumming, bleaching, deodorizing, and winterizing. Refined oils lack most of their original nutrients, along with their natural colors and aromas. Refining may also remove some of the fatty acids of an oil in order to prolong it's shelf-life.
Hydrogenated: Hydrogenation is chemical reaction commonly used in the processing of cooking oils, in which unsaturated fatty acids are turned into saturated ones by attaching a hydrogen atom to each carbon atom in order to reduce the bonds between them. This process is done in order to increase the shelf-life of the oil, as saturated fats are more stable than unsaturated fats. It is also cheaper than obtaining saturated oils from their natural sources (mainly animals and tropical plants) and produces a more solid substance. Hydrogenating oils alters their fatty acids and can turn them into 'trans-fatty acids', which are recognized in the body as toxic and have lead to many health problems.
Virgin: The term 'virgin' means that the oil has been extracted by mechanical means rather than with solvents and high heat, and is from the first-pressing.
Extra-Virgin: Extra-virgin means that the oil is 'virgin' but is also of high quality with exceptional flavor and aroma.
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References: View works cited for "Carrier Oils".
