Ethanol extraction is a type of solvent extraction used to extract fragrant compounds directly from dry raw materials, as well as the impure oils or concrete resulting from organic solvent extraction, expression, or enfluerage. Ethanol extracts from dry materials are called tinctures, while ethanol washes for purifying oils and concretes are called absolutes.
The impure substances or oils are mixed with ethanol, which is less hydrophobic than solvents used for organic extraction, dissolves more of the oxidized aromatic constituents (alcohols, aldehydes, etc.), leaving behind the wax, fats, and other generally hydrophobic substances. The alcohol is evaporated under low-pressure, leaving behind absolute. The absolute may be further processed to remove any impurities that are still present from the solvent extraction.
Ethanol extraction is not used to extract fragrance from fresh plant materials; these contain large quantities of water, which would also be extracted into the ethanol.
Famous quotes containing the word extraction:
“Logic is the last scientific ingredient of Philosophy; its extraction leaves behind only a confusion of non-scientific, pseudo problems.”
—Rudolf Carnap (18911970)