Essential oils are chemically very different from vegetable oils or other types of fats. Aromatic molecules are much smaller than in the case of fatty acids. These are carbon chains that generally have ten carbons. A few can have up to fifteen carbons, and some rare components even up to twenty carbons.
What characterizes essential oils, is the fact that they are volatile, which means that they evaporate completely on contact with air. If you put one drop of vegetable oil (such as rapeseed oil) on a piece of paper, it will create a stain that will remain on the surface. If you put a drop of essential oil on the same piece of paper, it will take a while, but in the end it will completely evaporate. Thanks to this property, the main attribute that we associate with essential oils is fragrance. It is also a property that allows us to extract essential oils by distillation.
Lipophilic properties of essential oils
Essential oils are lipophilic, which means that they can be easily absorbed by vegetable oils, waxes and fats. This property allows the formation of flower oils and is a prerequisite for an extraction process called enfleurage. The lipophilic properties of essential oils are very useful for the preparation of massage oils and oils used on face. This also means that externally applied essential oils are quickly absorbed into the skin and related tissues due to their highly oily content.
Hydrophobic properties of essential oils
Essential oils are hydrophobic, which means that they repel water. This property is necessary for the final stage of steam distillation, in which the essential oils are separated from the water. On the other hand, hydrophobicity prevents the use of essential oils in water-based products. It is generally not recommended to mix essential oils with water, as their layer only settles on the surface. Essential oils are partially soluble in alcohol. The amount of essential oils that can be mixed with alcohol depends on the particular essential oil and the percentage of alcohol.