Essential Oils are aromatic extracts of plants in a hydrophobic menstruum such as oil or alcohol. These extracts are volatile and readily disperse into the surrounding atmosphere. Research suggests that many essential oils have therapeutic applications for the benefit of human health.

What are Essential Oils?

Defining what essential oils are isn’t as straight-forward as one might think. At least; it wasn’t as straight-forward as I thought. I settled on using the following definition:

A non-water-soluble liquid containing a concentrated plant extract that readily evaporates at room temperature.

That definition contains three parts, so let’s break it down:

Non-Water-Soluble (hydrophobic): This means that a qualifying essential oil will not dissolve into water. Rather, it’s likely to float on the surface. This is part of the reason ultrasonic essential oil diffusers work so well.

Concentrated Plant Extract: Essential oils must contain plant extracts, in higher-than-natural concentrations. This requires a menstruum (solvent) such as alcohol or oil to extract the active plant compounds.

Readily Evaporated at Room Temperature: Essential oils worst by dispersing particles of their active ingredients throughout the air. Without this action, essential oils would be better categorized as “cream.”