What Are Essential Oils?

Essential oils are volatile, aromatic compounds produced by plants as part of their secondary metabolism. They are not actually oils in the chemical sense (they are not triglycerides), but they are called oils because they are lipophilic (fat-soluble) and immiscible with water.

What Are They Made Of?

Essential oils are complex mixtures of 20 to 200+ different organic compounds, primarily:

• Terpenes and terpenoids
• Phenylpropanoids
• Small-molecule alcohols, aldehydes, ketones, and esters

How Are They Produced by Plants?

Plants produce essential oils for several purposes:

• Defense against herbivores, fungi, and bacteria
• Pollinator attraction through fragrance
• UV protection for plant tissues
• Allelopathy — inhibiting competing plant growth

Extraction Methods

Steam Distillation

The most common method. Steam passes through plant material, carrying volatile compounds. The steam is condensed, and the oil separates from the water.

Cold Pressing

Used for citrus peels. Mechanical pressure ruptures oil glands and the oil is collected.

Solvent Extraction

Used for delicate flowers (jasmine, rose). Produces absolutes rather than true essential oils.