What Are Essential Oils?
Where do Essential Oils Come From?
Essential oils are the plant essences used in aromatherapy. They may be found in various parts of the plant. Rose (Rosa damascena) essential oil and hydrosol, for example, come from rose petals. Anise (Pimpinella anisum) essential oil is derived from anise seeds. Angelica (Angelica archangelica) essential oil is typically obtained from the roots. Other essential oils come from the leaves, bark, branches, resin, fruit, or peel. In most cases, it takes a huge amount of botanical material to produce even a small amount of essential oil.
Article:
Why You Need to Know Botanical Names »
Article: All About Hydrosols »
Article: Tips for Purchasing Essential Oils »
How Are Essential Oils Made?
In order to release and collect the essential oil and hydrosol from the plant, the relevant part of the plant is expressed, solvent extracted, or steam distilled. Expression is used primarily to obtain essential oils that come from fruit peels, such as grapefruit (Citrus paradisi) essential oil. Solvent extraction is necessary for some essential oils that would be destroyed by hot water and steam, such as jasmine (Jasminum officinale) essential oil, or those that are not sufficiently volatile to be extracted by steam distillation, such as benzoin (Styrax tonkinensis) essential oil.
Learn Therapeutic Uses, Aromatic and Distillation Information,
and Safety Precautions for Over 30 Aromatherapy Oils
in the Essential Oil Properties Database »
Most oils, however, are obtained by steam distillation, where steam is passed through the botanical material, releasing the volatile aromatic compounds when the heat causes the plant’s cell walls to burst. The essential oil molecules and steam are then cooled, resulting in condensation. Since oil and water are not mutually soluble, the non-water soluble fraction (the essential oil) is easily separated from the water-soluble fraction (the hydrosol or hydrolate) by pouring off the top layer or draining the bottom layer through a spigot in the collection vessel.
Learn More: Essential Oil Quality Control and Purity »
Though aromatherapy most often refers to use of the essential oil product of the distillation, the water layer coproduct (the hydrosol) often contains therapeutic substances as well, depending on the plant. Hydrosols do have therapeutic value, though this branch of aromatherapy is less widely known. It is important to know that hydrosols are obtained only through distillation, as expression and solvent extraction do not produce a water fraction coproduct.
Continue to Benefits of Aromatherapy »
Home | Articles
