Lab techs use state of the art equipment to create phase changes in carbon dioxide by utilizing temperature and pressure. The carbon dioxide is cooled and compressed to upwards of 10,000 psi – by comparison your car tire is pressurized to about 300 psi. When compressed to these extremes, CO2 becomes ‘supercritical’, which simply means that it converts to liquid when placed under extreme pressure.
There has been a fair amount of confusion surrounding the legality of CBD oil. But while the vast majority of cannabinoids are controlled substances under the Misuse of Drugs Act, rest assured that CBD oil is legal across the UK for medicinal purposes, provided it has been derived from an industrial hemp strain that is EU-approved. These strains contain very little to no THC (the psychoactive cannabinoid).
Considered the most scientific method this is also among the cleanest techniques of extraction. Referred to as sub-critical or super critical CO² method, it uses carbon dioxide under different pressures to extract the medicinal oil. This is among the most expensive techniques of extraction due to use of hi-tech equipment that can be operated by trained personnel only. The advantage of this technique is that the end product is the purest form of CBD oil which is highly potent and free of chlorophyll. However if the heat used during extraction is too high it can damage terpenes in the oil that have therapeutic benefits and provide flavor and essence to the oil strain.
Zuardi, A. W., Crippa, J. A., Hallak, J. E., Bhattacharyya, S., Atakan, Z., Martin-Santos, R., … & Guimarães, F. S. (2012). A critical review of the antipsychotic effects of cannabidiol: 30 years of a translational investigation [Abstract]. Current Pharmaceutical Design, 18(32), 5,131–5,140. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/22716160