HOW DO WE GET THEM?
Most essential oils are extracted by steam distillation, although some are obtained by solvent extraction and others, like the citrus oils, by expression.DISTILLATION
The most widely used and, as yet, the best way of obtaining the purest essential oils. However, the high temperatures involved make it less suitable for the more exotic fragrances such as Rose, Neroli or Jasmine.SOLVENT EXTRACTION
The plant material is put into a still and then heated with water, steam or both. The intense heat causes the tiny sacs containing the oils to burst, releasing their contents into the resulting vapour. This is then channelled into a condenser and cooled, causing it to become liquid once more. The liquid, which now consists of oil and water, is separated off, leaving the pure essential oil, and a floral or herbal water.
This is the most popular method of obtaining highly fragrant floral oils, although a slightly modified method can be applied to gums and resins. Here, the plant material is placed in a container with the solvent and heated so that the solvent can extract the oils. The resulting mixture is then filtered and becomes what is known as a "concrete". The concrete is then mixed with alcohol, chilled, filtered and the alcohol then evaporates off, leaving behind the highly perfumed oil which is called an "absolute". More advanced methods of solvent extraction have reduced the need for alcohol.EXPRESSION
This applies only to citrus oils. Here, the rinds, or zests, are simply squeezed by a machine (or sometimes by hand) to release their oils.ENFLEURAGE
A highly specialised and little used method of extraction reserved for high quality flower oils. Freshly harvested petals are spread on fat on top of glass frames and replaced every 24 hours as the fat becomes saturated with essential oils. The resulting compound, now called a "pomade", is washed with alcohol which is then evaporated off, leaving the fragrant oil.MASCERATION
A process in which flowers are steeped in hot fat which absorbs the oils. The plant material is then removed leaving an "infused" oil.