Best perfume: Obtaining natural odorants

Before perfumes can be composed, the odorants used in various perfume compositions must first be obtained. Synthetic odorants are produced through organic synthesis and purified. Odorants from natural sources require the use of various methods to extract the aromatics from the raw materials. The results of the extraction are either essential oils, absolutes, concretes, or butters, depending on the ammount of waxes in the extracted product. All these techniques will, to a certain extent, distort the odor of the aromatics compounds obtained from the raw materials. This is due the use of heat, harsh solvents, or through exposure to oxygen in the extraction process which will denature the aromatic compounds, which either change their odor character or renders them odorless.

- Maceration/Solvent extraction

The most used and economically important technique for extracting aromatics in the modern perfume industry. Raw materials are submerged in a solvent that can dissolve the desired aromatic compounds. Maceration last anywhere from hour to months. Fragnance compounds for woody and fibrous plant materials are often obtained in this manner 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. Commonly used solvents for maceration/solvent extraction include hexane, and dimethyl ether. The product of this process is called a "concrete"

a) Supercritical fluid extraction

A relatively new technique for extracting fragnant compounds from a raw material, which open employs Supercritical CO2. Due to the low heat of process and the relatively nonreactive solvent used in the extraction, the fragnant compounds derived often closely resemble the original odor of raw material.

b) Ethanol extraction

A type of solvent extraction used to extract fragnant compounds directly from dry raw materials, as well as the impure oily compounds materials resulting from solvent extraction or enfleurage. Ethanol extraction is not used to extract fragnance from fresh plant materials since these contain large quantities of water, which will also be extracted into the ethanol.

- Distillation

A common technique for obtaining aromatic compounds from plants, such as orange blossoms and roses. The raw material is heated and the fragnant compound are recollected through condensation of the distilled vapour.

a) Steam distillation

Steam from boiling water is passed through the raw material, which drives out their volatile fragnant compounds. The condensate from distillation are settled in a Florentine flask. This allows for the easy seperation of the fragnant oils from the water. The water collected from condensate, which retains some of the fragnant compounds and oils from the raw material is called hydrosol and sometimes sold. This is most commonly used for fresh plant materials such as flowers, leaves, and stems.

b) Dry/destructive distillation

The raw materials are directly heated in a still without a carrier solvent such as water. Fragnant compounds that are released from the raw material by the high heat often undergo anhydrous pyrolysis, which results in the formation of different fragnant compounds, and thus different fragnant notes. This method is used to obtain fragnant compounds from fossil amber and fragnant woods where an intentional "burned" or "toasted" odor is desired.

c) Fractination

Through the use of a fractination colomn, different fractions distilled from raw material can be selectively excluded to manipulated the scent of the final product. Although the product is more expensive, this is sometimes performed to remove unpleasant or undesireable scents of a material and affords the perfumer more control over their composition process.

- Expression

Raw material is squeezed or compressed and the oils are collected. Of all raw materials, only the fragnant oils from the peels of fruits in the citrus family are extracted in this manner since the oil is present in large enough quantities as to make this extraction method economically feasible.

- Enfleurage

Absorption of aroma materials into wax and then extracting the odorous oil with ethyl alcohol. Extraction by enfleurage was commonly used when distillation was not possible because some fragnant compounds denature through high heat. This technique is not commonly used in the present day industry due to its prohibitive cost and the existence of more efficient and effective extraction methods.