Essential oils are obtained by various methods depending on the oil species. Delicate flower scents need extracting differently from those from leaves or roots. The main methods are explained below.

Enfleurage
Enfleurage is an expensive process and is very rarely used today. Some flowers, such as jasmine or tuberose, have very low contents of essential oil and are extremely delicate and the heat involved in steam distillation would destroy the blossoms before releasing the essential oils. Here the flower petals are placed on solid sheets of warm fat, which will absorb the flowers' essential oils. When all the fragrance is transferred from the flowers to the fat they are removed and replaced with fresh ones. This process is repeated several times until the fat becomes saturated with the essential oil. A solvent, most of the time alcohol, is then added which separates the essential oil from the fatty substance (know as pomade). The alcohol will then evaporate leaving only the essential oil.

Distillation
Steam distillation is the most common method of extracting essential oils. This involves filling the still with fresh, (occasionally dried) botanical material. Then pressurized steam is generated which enters the container and circulates through the plant material. The heat of the steam forces the pockets that hold the essential oils to open, thus releasing them into the steam. These tiny droplets of essential oil attach to the steam, then travel up a long tube surrounded by cold water. The cold forces the steam to cool and condense back into the water containing the oils. As Essential oils do not mix well with water, in time it settles as a film on the water's surface. To separate the essential oil from the water, the film is then decanted or skimmed off the top leaving the hydrolat.

Expression
Cold pressed expression is used to obtain essential oils from the peels and seeds of citrus fruits, such as Bergamot, Grapefruit, Lemon, Lime and Orange. In this process the fruit rolls over a trough with sharp projections that penetrate the peel which then pierce the tiny pouches containing the essential oil. Then the whole fruit is pressed to squeeze the juice from the pulp and to release the essential oil from the pouches. The essential oil rises to the surface of the juice and is then separated from the juice.

Solvent Extraction
Solvent extraction uses very little heat so it is able to produce essential oils from plants whose fragrance would be destroyed or altered during steam distillation. Solvent extraction is used almost exclusively on delicate plants and produces higher amounts of essential oils at a lower cost than could be achieved by enfluage. In this process, a chemical solvent such as hexane is used to saturate the plant material and pull the essential oils out. The plant material is then removed and this renders a solvent. The solvent is then boiled off under a vacuum or in a centrifugal force machine to help separate it from the oil. Because the solvent has a lower boiling point than the essential oil it evaporates and the oil is left. The solvent is cooled back into liquid and recycled. Along with the essential oil, the fats, waxes and heavier oils are extracted producing a substance known as a concrete. The process is continued by dissolving oils into warm alcohol. The alcohol is removed under a vacuum and an absolute is left.

Carbon Dioxide
Another method of extraction for delicate plants is by use of carbon dioxide. Using carbon dioxide in a state known as hypercritical at high pressure, it becomes a very effective solvent which does not contaminate the oils. However oils produced by this method are very expensive.

Although there is much debate regarding this method, what is certain is that this method produces an oil which smells very close to the original with Rose or Chamomile Absolute smelling much different from their steam distilled counterparts (much more pleasant). Also, now that hexane (a hydrocarbon) is used as the solvent material the solvent residue is around 10 ppm (parts per million) and is therefore almost undetectable in the resulting product.