What is supercritical CO₂

When a substance is taken above its critical temperature and critical pressure it becomes a supercritical fluid. The clear boundary between liquid and gas disappears: the fluid spreads into pores like a gas and dissolves compounds like a liquid.

For CO₂ this threshold is about 31 °C and 73.8 bar. This relatively mild temperature makes CO₂ a common extraction agent for botanicals. CO₂ is not flammable and turns back into gas when pressure is released, so it largely leaves the extract. What remains, and the other properties of the product, are assessed by analysis.

The critical point is a physical property of the substance. A facility's operating pressure and temperature are chosen separately above that threshold, for the target compound and the raw material.

Source: puritycall.com blog, “what is supercritical CO2 extraction?”, 15 December 2024; rewritten. A general information note, not a certificate of analysis for purity call products.

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