Essential oils are natural aromatic extracts from plant materials including herbs, leaves, flowers, needles, twigs, fruit peels, seeds, bark and roots. These oils are used in aromatherapy and other natural products. There are several methods used to extract essential oils from plants, each with its own advantages and disadvantages. The most popular method for extracting essential oils is steam distillation.
This process occurs when the steam vaporizes the volatile compounds of the plant material, which eventually go through a process of condensation and collection. This method is energy and solvent intensive, making it expensive. Before distillation was invented, “expression” was one of the main methods used to extract essential oils from plants. This method uses mechanical pressure to expel the oil from the plant material.
The shells are immersed in warm water and the oil is expelled from the material under high mechanical pressure. CO2 extracts are produced by a process called supercritical fluid extraction. This method uses carbon dioxide as a solvent to extract essential oils from plant material. Due to the liquid properties of gas, CO2 functions as a solvent in natural plant matter, extracting oils and other substances such as pigment and resin from plant matter.
This method produces very pure oils with a unique quality, so they can differ greatly from steam distilled essential oils. Absolutes are also produced by solvent extraction. This specially designed container has two outlets in view of the fact that oil and water do not mix, i.e. The oil and juice that are produced still contain fruit solids, such as peel, and must be centrifuged to filter solids from liquids. CO2 extracts are usually thicker than their essential oil counterparts and often give off more aroma from natural herb, spice or plant than a distilled essential oil. You might think that CO2 extracts have both the lightest molecules of an essential oil and the heaviest molecules of an absolute. Each method of extracting essential oils has its own advantages and disadvantages.
Steam distillation is energy and solvent intensive but produces pure essential oils with unique qualities. Expression is a mechanical process that is less expensive but produces lower quality oils. CO2 extraction produces pure oils with unique qualities but is expensive due to its complexity. Absolutes are produced by solvent extraction but require additional processing to remove solids.
