CO2 extraction

CO2 extraction uses pressurized carbon dioxide, in a liquid or supercritical state, as the solvent that pulls cannabinoids and other compounds out of hemp.

Above a certain pressure and temperature, carbon dioxide becomes supercritical, behaving like both a gas and a liquid, and it dissolves plant oils efficiently. Adjusting pressure and temperature changes which compounds are pulled out, and operators may use lower, subcritical settings to favor more delicate constituents. When the pressure is released the carbon dioxide returns to a gas and leaves the extract, so it does not remain as a residual solvent.

The equipment is expensive and the process is slower than solvent extraction, but the resulting crude extract typically needs less cleanup for solvent residue. The method does not by itself determine the cannabinoid profile of a finished product; that depends on the plant material and on subsequent refining steps such as winterization and distillation. A certificate of analysis, not the extraction method, is what shows what ended up in the product.