Absolutes

Absolutes are similar to essential oils in that their are concentrated mixtures of oily frangrance compounds derived from plants. But while essential oils refer to any type of concentrated fragrant oil extracted through the any process, including distillation, expression, or sometimes supercritical CO₂ extraction, absolutes are typically made using a two step process. An organic solvent is first used to extract all hydrophobic compounds from the raw material producing the concrete, then the lower molecular weight fragrant compounds are extracted from the concrete using ethanol, which produces the absolute.

Depending on the type of essential oil, absolutes usually have higher concentrations of fragrant compounds due to the efficiency of the extraction and the low temperature of the process, which both prevent many of the fragrant compounds from becoming damaged. Absolutes may contain traces of the solvents used in the extraction, and as such their use in aromatherapy are perceived by some to be undesirable.

Absolutes are used extensively in perfumery applications, since, the absolute will be closer in aroma to the original plant when compared to oil produced through distillation, the second most common method for extracting fragrance materials. Examples of this are rose otto (steam distilled rose oil) and rose absolute or neroli (steam distilled oil from the blossom of the bitter orange tree) and Orange Blossom Absolute.

Some botanicals, however, are too delicate to be steam distilled so can only yield their aroma via the process of solvent extraction. Examples of this are Jasmine, Tuberose, and Mimosa.