CO2 extraction
CO2 extraction uses pressurized carbon dioxide to recover aromatic material. Learn what select and total extracts mean and how the process differs from steam.
Updated
CO2 extraction uses pressurized carbon dioxide as a solvent to recover compounds from a raw material. Changing the pressure and temperature changes what it can dissolve. After extraction, reducing the pressure separates the carbon dioxide from the recovered material.
Supercritical extraction is one form of the process: carbon dioxide is held above its critical temperature and pressure. It can operate at lower temperatures than steam distillation, which makes it useful for some heat-sensitive materials.
A CO2 extract is not necessarily the same composition as an essential oil, nor is it always a thin liquid. Extraction conditions can recover waxier or less volatile substances as well as aroma. Choose by the actual material and specification, not the technique’s reputation alone.
- Supercritical fluid
- A substance above its critical temperature and pressure, with properties useful for extraction.
- Subcritical extraction
- A process using conditions below the critical point. CO2 extraction does not always mean supercritical extraction.
- Select extract
- A supplier term commonly used for an extract focused on more volatile components. Check the specific specification.
- Total extract
- A supplier term for a broader extract that may include less volatile, waxy or fatty components.
- Pressure and temperature
- Process controls that help determine the range of compounds recovered.
- CO2 vs. steam
- CO2 acts as a solvent under pressure; steam distillation recovers volatile material through evaporation and condensation. Their extracts can differ.