CO₂ extracts

A CO₂ extract is made using pressurized carbon dioxide as the extraction medium. Changing the pressure and temperature changes its solvent properties, allowing different portions of a botanical material to be gathered.

How the process works

Carbon dioxide is brought into contact with the plant material under controlled conditions. In supercritical extraction, it is held above a particular combination of temperature and pressure. After extraction, reducing the pressure allows the carbon dioxide to separate from the collected material.[1,2]

What CO₂ gathers

CO₂ can recover volatile aromatic constituents as well as less volatile, fat-compatible materials. Depending on the plant and process, these may include fatty oils, carotenoid pigments, waxes, plant sterols and vitamin E compounds.

Research comparing methods for extracting sea buckthorn seed and pulp oils examined several of these constituent groups, illustrating how CO₂ extraction can produce a botanical oil rather than only an aromatic concentrate.[3]

Other CO₂ extracts are selected primarily for their fragrance. Some are fluid; others are thicker or waxier.

Reading the ingredient

“CO₂ extract” identifies the extraction medium. The plant, plant part and selected process determine what kind of material results: an aromatic extract, a fatty oil or a mixture of volatile and nonvolatile constituents.

This gives CO₂ extracts a place in both natural perfumery and skincare, depending on the composition being sought.

Related entries: Extraction & solubility; Essential oils; Absolutes; Plant oils, butters & waxes.