Essential oils are highly concentrated aromatic oils extracted from plants. Depending on the plant, the oil may come from its flowers, leaves, stems, bark, wood, roots, fruit peels, or resin. Different plants require different extraction methods to capture their natural aromas.
Steam Distillation
Steam distillation is the most common method used to produce essential oils. Plant material is placed inside a still and exposed to steam. The heat releases the plant's volatile aromatic compounds, which travel with the steam into a condenser.
As the vapor cools, it becomes liquid again. The essential oil naturally separates from the aromatic water, allowing the oil to be collected. The remaining aromatic water is commonly known as a hydrosol.
Lavender, patchouli, peppermint, eucalyptus, rosemary, and many wood oils are commonly produced using steam distillation.
Cold Pressing
Cold pressing, also called expression, is commonly used for citrus oils. The outer peel of the fruit contains tiny pockets of aromatic oil. Mechanical equipment breaks open these pockets and separates the oil from the water and juice.
Orange, lemon, grapefruit, and other citrus oils are commonly produced this way.
Solvent Extraction
Some delicate flowers and botanical materials don't respond well to the heat involved in steam distillation. Solvent extraction can be used to capture their aromatic compounds.
Jasmine is a well-known example. The resulting concentrated aromatic material is generally called an absolute rather than an essential oil.
CO₂ Extraction
Another method uses carbon dioxide under controlled pressure to extract aromatic compounds from plant material. Once extraction is complete and the pressure is reduced, the carbon dioxide dissipates, leaving the concentrated botanical extract behind.
Where Do Popular Oils Come From?
Patchouli – Steam distilled from patchouli leaves.
Cedarwood – Steam distilled from aromatic wood material.
Lavender – Steam distilled primarily from lavender flowering tops.
Eucalyptus – Steam distilled primarily from eucalyptus leaves.
Peppermint – Steam distilled from the leaves and flowering portions of the peppermint plant.
Rosemary – Steam distilled from the leaves and flowering tops.
Clove – Commonly steam distilled from clove buds. Clove leaf and stem oils are also produced.
Orange – Usually cold pressed from the outer peel.
Lemon – Usually cold pressed from lemon peel.
Grapefruit – Usually cold pressed from grapefruit peel.
Ginger – Commonly steam distilled from the ginger rhizome.
Frankincense – Distilled from the aromatic resin of Boswellia trees.
Sandalwood – Traditionally steam distilled from sandalwood heartwood and roots.
Jasmine – Most commonly solvent extracted from jasmine flowers to produce an absolute.
Vanilla – Vanilla does not produce a conventional steam-distilled essential oil. Vanilla aromatic products may instead be extracts, absolutes, CO₂ extracts, oleoresins, or other preparations.
Nag Champa – Nag Champa is not a single essential oil. It is an aromatic blend traditionally associated with ingredients such as sandalwood and floral materials including champaca. Formulations can vary considerably.
Essential Oils vs. Naturally Scented Oils
It is important to understand that the terms essential oil and naturally scented oil do not always mean the same thing.
A genuine essential oil is derived from botanical material through processes such as steam distillation or expression. Naturally scented products may also incorporate botanical extracts, absolutes, resins, and other naturally derived aromatic materials.
At Scentsium, we believe understanding where aromas come from is an important part of appreciating naturally scented products. Different plants require different extraction techniques, but they all begin with the remarkable aromatic compounds found in nature.