What are Essential Oils?

Aromatic plants produce fragrant essences in secretory cells, using nutrients from the soil and water, and light and warmth from the sun in a process called photosynthesis. These naturally occurring plant essences attract beneficial insects, such as bees, to help pollination and deter less friendly insects that would otherwise eat or damage the plant.

In many aromatic plants the secretory cells are near the surface, located in flowers and leaves. When you walk past these plants and brush against them, this releases the fragrance into the air. The beauty and magic of these essences are often described as the aromatic heart, life force or energy, and soul or spirit of the plant. When aromatic plants are distilled (usually by steam distillation), the essences undergo subtle chemical changes and turn into essential oils.

The term ‘essential oil’ is generally applied to all the aromatic oils used in aromatherapy, although strictly speaking this is not technically correct. Oils extracted from citrus fruits using simple expression of the rinds are still the plant essence. Some floral oils, such as jasmine, are obtained by a process called enfleurage or solvent extraction. This produces a ‘concrete’, which then undergoes further solvent extraction to produce an ‘absolute’. However, for ease and simplicity, the term ‘essential oil’ is often used generally to mean all aromatherapy oils.

Main Characteristics of Essential Oils

Many essential oils are light, clear and non greasy, although a few are viscous and some are coloured. However, they all share one important characteristic: they will only dissolve in fatty oils, such as almond or sunflower oil, or in alcohol. They will not dissolve in water, and this has implications for the way they are used.

Essential oils are very concentrated and powerful, and are greatly diluted before use in aromatherapy. In a massage oil, for example, the dilution of essential oil in base oil is around 2 or possibly 3 percent. Essential oils are only rarely used undiluted, and in very specific instances. They are also highly volatile and evaporate quickly when exposed to the air, so they are best kept in airtight, dark glass bottles.