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With a strong emphasis currently on the cannabinoid concentrate consumables market, it would appear as though extraction-based products are the future of cannabis consumables. There are currently two main alternatives for extraction process and these are through the use of: (1) supercritical carbon dioxide (scCO2), a relatively new method, and (2) ethanol.
Supercritical extraction process is a method under which carbon dioxide is used under supercritical conditions, as a solvent to solubilize organic components of biomass that has been placed in an extraction vessel. Through the supercritical pressure of the CO2, the fluid is able to retain its penetration properties of a liquid, but increase the speed at which the material can diffuse into the solvent. Once the biomass has been carried out of the system as the solvent, it is depressurized, meaning that the carbon dioxide is removed. This is one of the main advantages of this process as the products created are extremely pure. However, one of the main drawbacks of this process is the requirements to do “winterization”, where the high melting point lipidous materials are removed, creating an additional step in preparing the final product. Additionally, another benefit is the end product has a much lower level of toxicity in comparison to other methods. This is because carbon dioxide is considered to be a relatively safe solvent, especially when compared to the standard organic alternatives, such as benzene, which is a highly toxic carcinogenic. Also, because of the relatively low operating temperatures, the terpene and the cannabinoid portorios are preserved with little to no degradation. Finally, due to the inert nature of carbon dioxide, it will not alter the chemical compositions of the extracts.
Ethanol is a much simpler process of extracting cannabinoids, with a lower initial capital outlay, in most cases, than the supercritical process. This method utilizes ethanol as the solvent for the biomass to be suspended in before extracting the cannabinoids. Once the biomass has been submerged, the ethanol is drained from the container, and the biomass is pressed to remove any excess ethanol. All the recovered solution collected is then heated to boil off the alcohol, leaving only the cannabinoids, which were extracted during the time that the cannabis was suspended in the solvent. The more advanced method of this process adds an additional step of mechanically agitating the cannabis and solvent mixture. This is often done to increase the extraction yield of the cannabinoids to increase overall efficiencies. The product of this extraction varies not only on the advanced nature of the system, but also on the operating temperature during suspension. Systems range in operating temperature from room to cool, which dictates the yield and purity inversely. The cooler the operating temperature, the lower the yield, but the higher the purity and vice versa. In systems that operate at a cooler temperature, the product may be so pure that no further purification is required. Warmer systems on the other hand may require an additional purification stage called dewaxing, which is minor in comparison to the winterization stage of the supercritical extraction process.
In summary, both systems are relatively efficient, yielding greater than 90% extraction, if done correctly. Although on average the supercritical method will yield a higher efficiency, there is a trade off in terms of initial capital outlay and the added difficulties of winterization. Ethanol is currently the more common practice for extraction process, however, in order to achieve similar results to that of the supercritical method, more advanced technology is required, minimizing the advantage of a reduced initial capital outlay.
