Subcritical Fluid Extraction
Subcritical Fluid is used to retain essential oils terpenes
Subcritical Extraction produces a lighter colored extract, fewer waxes and resins, and retains significantly more volatile oils
Subcritical Fluid Extraction (ASE | PSE)
Subcritical fluids are fluids which are compressed below their critical temperatures, yet kept in the liquid state and used above their boiling points with the use of pressure.
Subcritical fluids are also referred to as hot liquid solvents or pressurized liquid solvents, and the process can be referred to as PSE or ASE (pressurized or accelerated solvent extraction).
The solvent power of subcritical fluids is dependent on the temperature utilized, while unlike in SFE, pressure changes have a negligible effect on the resultant solvent properties. Therefore, temperature helps to increase solvency, while pressure is used to help retain the liquid state of the fluid.
Preserve Sensitive Compounds
Subcritical extractions at low temperature and low pressure take more time but they can be used to retain the essential oils terpenes and other sensitive chemicals within the plant.
Subcritical CO2 extraction is generally preferred because it produces a lighter colored extract, fewer waxes, and resins, and retains significantly more volatile oils compared to supercritical CO 2 extraction. Subcritical extraction methods, in comparison, are slower and produce smaller yields as less of the plant matter gets used.
Following a subcritical run with a supercritical extraction is a preferred methodology, scrubbing the matrix of any remaining valuable compounds and achieving a full-spectrum extraction.