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Fragrance extraction


Fragrance extraction refers to the extraction of aromatic compounds from raw materials, using methods such as distillation, solvent extraction, expression, or enfleurage. The results of the extracts are either essential oils, absolutes, concretes, or butters, depending on the amount of waxes in the extracted product.

To a certain extent, all of these techniques tend to distort the odour of the aromatic compounds obtained from the raw materials. Heat, chemical solvents, or exposure to oxygen in the extraction process denature the aromatic compounds, either changing their odour character or rendering them odourless.

Certain plant materials contain too little volatile oil to undergo expression, or their chemical components are too delicate and easily denatured by the high heat used in steam distillation. Instead, the oils are extracted using their solvent properties.

Organic solvent extraction is the most common and most economically important technique for extracting aromatics in the modern perfume industry. Raw materials are submerged and agitated in a solvent that can dissolve the desired aromatic compounds. Commonly used solvents for maceration/solvent extraction include hexane, and dimethyl ether.

In organic solvent extraction, aromatic compounds as well as other hydrophobic soluble substances such as wax and pigments are also obtained. The extract is subjected to vacuum processing, which removes the solvent for re-use. The process can last anywhere from hours to months. Fragrant compounds for woody and fibrous plant materials are often obtained in this matter as are all aromatics from animal sources. The technique can also be used to extract odorants that are too volatile for distillation or easily denatured by heat. The remaining waxy mass is known as a concrete, which is a mixture of essential oil, waxes, resins, and other lipophilic (oil-soluble) plant material, since these solvents effectively remove all hydrophobic compounds in the raw material. The solvent is then removed by a lower temperature distillation process and reclaimed for re-use.


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