What is the difference between an Essential Oil, Concrete, Absolute & Resinoid?
An Essential Oil, Concrete, Absolute & Resinoid are all different types of concentrated plant extracts, but they differ in their extraction method, chemical composition, and properties.
An essential oil is a highly concentrated liquid that is extracted from plant materials using steam distillation or cold pressing. Essential oils are volatile and highly aromatic, and contain the characteristic fragrance and chemical constituents of the plant.
Solvent extraction is typically used for delicate flowers and other plant materials that cannot withstand the high temperatures used in steam distillation.
During solvent extraction the raw material and solvent are placed in a distillation vessel and gentle heat is applied.
What is left after the solvent has been removed is a near solid wax-like substance called a 'concrete'. Where resinous botanical material has been used to extract, the result would be called a 'resinoid' instead of a 'concrete'. (for example frankincense or myrrh).
An absolute is made by taking the concrete and melting it by warming with some alcohol and then stirring it. The essential oil, some waxes, fixed oils and fats then dissolve in the alcohol.
The alcohol mixture is then distilled in a vacuum to remove the alcohol, and the remaining substance is an 'absolute'.
Absolutes have a strong, true-to-life aroma and are the most concentrated form of fragrance (and the most costly).
In conclusion, while all of these extracts come from plants and are used for similar purposes, they differ in terms of their extraction method, chemical composition, and properties