Every living organism has a life force, energy or ‘soul’ which it is impossible to get hold of or to see. The life force of a plant is also something that cannot be seen or touched, and it has been said that it is contained in the essential oil of a living plant. It is the ‘heart’ of a plant and is present in only very, very small quantities, sometimes as little as .01 per cent. It is the energy from the original life force of the plant which we introduce into the body by aromatherapy, each oil having its own curative effect on certain parts of the body and its systems as well as greatly influencing the mind.
During the life of the plant the essential oil cells (distributed throughout the leaves, flowers, stems, bark or root in minute odiferous droplets) change their chemical composition according to the time of day or the season of the year. It is therefore important to gather herbs and plants for therapeutic use, or distillation into essential oils, at exactly the right time.
Only oils obtained by steam distillation and expression can be truly classed as essential oils; those obtained by using some kind of solvent being known as absolutes or resins.
The cost of producing essential oils is not only in direct proportion to the quality of the plant (soil quality etc) but is also dependent on the quantity of oil-producing glands present in the plant.
The strength at which an essential oil is used is very important to remember, because some, if applied or taken in excess, or if too strong, have the reverse effect to that which is desired. For example, a low concentration of peppermint oil applied to an itchy skin will relieve the irritation; a strong concentration will aggravate the condition.
The volatility rate varies in different oils, and most essences fall into one of the three classifications:
Top notes : the fastest acting, the quickest to evaporate, the most stimulating and uplifting to mind and body.
Middle notes : moderately volatile, Primarily effect the functions of the body e.g. digestion, menstruation and the general metabolism of the body.
Base notes : slower to evaporate, The most sedating and relaxing.