Frequently Asked Questions
There are other concentrated oils which are used in Aromatherapy which have been extracted via a method other than distillation. Technically not essential oils there are, nevertheless, medicinally beneficial and aromatic. They include resinoid, absolutes and essences.
Essences are oils extracted via a mechanical method. They do not contain all the chemicals from the plant and generally have a shorter shelf life. This method is used primarily to extract essences from the peel of citrus fruits such as lemon, orange, lime, bergamot, grapefruit mandarin, and tangerine. Distillation is not an option since the heat may destroy the volatile liquid.
Concretes require a hydrocarbon solvent such as petroleum ether, butane, or hexane introduced to the plant material. The result is a “concrete” composed of hydrocarbons and traces of the plant chemicals. It generally has a waxy feel and solidifies in cold temperatures and retains only trace amounts of the original solvent. Rose, Neroli, Immortelle, and Oakmoss can be effectively extracted this way.
Resinoids are a thick, solid or semi-solid substance extracted from the lower part of a tree. Hydrocarbon based solvents, typically benzene, hexane or various alcohols are added where they attach to and extract various molecules. The solvent is then mostly evaporated or removed by distillation leaving a thick resinous liquid (benzoin, frankincense, myrrh). The price of a resinoid can be influenced greatly by the quality of the solvent. Further dilution with alcohols may be required to maintain liquid state.
Absolutes are created from a concrete by washing the waxy substance in alcohol to remove aromatic compounds. The alcohol is then gently evaporated off. Most modern operations use a vacuum to speed up the process without losing any of the vital aromas. A dark green, reddish or golden aromatic liquid is then left behind. This is the only way to extract Jasmine. There is no essential oil of Jasmine, only an absolute. Rose can be extracted through distillation or this method.