CO2 extraction

CO₂ extraction uses pressurized carbon dioxide as a tunable solvent to isolate cannabinoids and terpenes from cannabis biomass. CO₂'s critical point sits at 31.1°C (88°F) and approximately 1,071 PSI (7.4 MPa / 74 bar). Above that threshold the fluid is supercritical — combining gas-like diffusion with liquid-like solvency — while below it, liquid CO₂ is subcritical, gentler and more selective but lower-yielding. Tuning pressure and temperature across the phase diagram allows extractors to target different fractions of the plant's chemistry. Supercritical parameters run at commercial scales of 1,500–5,000 PSI (100–350 bar) and 40–60°C (104–140°F). A widely cited optimized protocol (MDPI Processes, 2023) runs 235 bar, 55°C, 15 g/min CO₂ flow, for 2 hours. Subcritical parameters run below 31.1°C and/or below 1,071 PSI, commonly 10–30°C and 600–1,000 PSI. Fractional extraction steps pressure and temperature through multiple targets — a subcritical pass to capture monoterpenes, followed by a supercritical pass for cannabinoids and waxes. Ethanol co-solvent (0–40%) substantially increases yield but triggers downstream winterization and ethanol residual-limit obligations. Supercritical CO₂ crude typically requires winterization before distillation. Yield runs 4.9–26% depending on conditions — generally lower than hydrocarbon or ethanol extraction. Supercritical CO₂ technology was developed for decaffeinated coffee production in 1970s Germany; Apeks Supercritical (2001), Eden Labs, and Waters brought dedicated cannabis SFE machines to the U.S. market across the 2010s. Regulatory treatment is comparatively light: CO₂ is not typically regulated as a residual solvent because it is non-toxic, GRAS, and vents as a gas; extraction rooms are commonly classified C1D2 rather than C1D1. Any ethanol co-solvent or winterization step immediately brings ethanol residual limits back into scope. ⚠️ Marketing that positions CO₂ extraction as inherently "cleaner" is undercut by the fact that post-processing almost always involves ethanol, and supercritical temperatures and pressures can degrade volatile monoterpenes. Capital costs of $150,000 to $1M+ per production system represent a substantial barrier to entry. → See also: Distillate, Ethanol extraction, BHO, Extract