Essential oils are produced from various plant parts from which the essence of the plant is extracted to form the oil. The oils are used for their presumed health-giving benefits in aromatherapy, in food flavorings and in the perfume and cosmetics industries. Some oils are also used as disinfectants and for their anti-bacterial properties. The majority of oils are extracted through the process of steam distillation.
The History of Steam Distillation
According to Scienceray.com: “A Persian chemist, Ibn Sina invented the process of steam distillation in early 11th century in order to extract the essential oils from their sources. Its invention led to a kind of revolution in the industry of perfumery.” His process was so good that no improvements were made to it for over 200years, and although refinements have been made since, the system remains the same even today.
The Process of Steam Distillation
Steam is introduced at high pressure into a retort containing the plant parts. The steam passes through the plant material, saturating it with water which bursts the molecules of essential oil. The vapor given off from this process, a mixture of steam and essential oil, then passes from the top of the retort through the condenser--a spiral tube immersed in cold water--which cools the vapor as it flows through it and into the separator. The mixture of oil and water then separates, with the oil floating to the top. The water is drawn off from the bottom, leaving the essential oil.
Byproducts of Steam Distillation
The drawn-off water, known as the hydrolat or floral water, is often used as a byproduct of the process. For example, rosewater is a byproduct of the extraction of rose essential oil. Other floral waters include lavender water, jasmine water and orange flower water. Says Esoteric Oils: "Floral waters are often used as an ingredient in skin toners and tonics, yet on their own can also be used for a quick pick-me-up by simply spraying them onto the skin, or in the air."
The Nature of Essential Oils
Essential oils are extracted from the flowers, seeds, leaves, roots, bark and fruits of plants, shrubs and trees. Says the International Federation of Aromatherapists: “Each essential oil has its own chemical identity, which produces unique properties. Essential oils can be antiseptic, analgesic, anti-inflammatory, anti-infectious and so on. They can be used to stimulate or sedate, and their powers to heal can be applied to physical, mental and emotional conditions.”
It should be noted however, that the use of essential oils is never a substitute for professional medical care.
Oils Produced by Steam Distillation
The majority of essential oils, of which there are over a hundred, are produced by steam distillation. Citrus fruits are generally produced by expression, when the oil is literally pressed out from the fruit, and some other oils by using chemicals to extract the oils. The most popular oils, such as lavender, tea tree, eucalyptus, geranium, clary sage and frankincense, are all produced through the process of steam distillation.
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