Why CO2 is Best in the Cannabis Extraction Industry
Across the country – and around the world – cannabidiol or CBD has exploded into popularity. And, despite newer methods arising constantly, the tried and true method of CO2 extraction has proven to be the safest, most efficient method in the industry. While some may disagree, this article will lend itself to the fact that CO2 is a staple cannabis extraction technology that is going nowhere anytime soon.
Supercritical CO2 extraction has always been used in a wide array of extraction procedures from essential oils to decaffeination of coffee. In addition, it can be used to extract botanical oils from nearly any plant material. Among the plants most frequently used in supercritical CO2 extraction, cannabis is growing in popularity when it comes to extracted products. While there are various methods to extract cannabinoids from the cannabis plant, CO2 is likely the safest and most efficient option for extractors and customers alike.
What is Supercritical CO2?
To put it simply, supercritical CO2 extraction uses carbon dioxide in specific temperatures and pressures to extract desirable cannabinoids from hemp or cannabis biomass. With the combination of special temperatures and pressures, CO2 reaches what is called a supercritical state. This is an important factor in the CBD extraction procedure which permits a complete extraction at an efficient throughput.
You may be asking what supercritical means and why it matters in regards to creating cannabis extracts. Let us take a look at the procedure from start to finish inside a supercritical CO2 extractor to learn how this extraction procedure works.
To get an idea of how this extraction process works, let’s run through three quick steps that explain how CO2 is used in supercritical conditions as an extraction solvent:
- The Supercritical CO2 extractors make use of carbon dioxide (CO2) at a heightened temperature and increased pressure to extract hemp or cannabis compounds from plant biomass. Carbon dioxide above the critical temperature (31ºC) and pressure (1071 psi) turns into a supercritical fluid, which has an extended functionality of solubilizing non-polar compounds.
- Under supercritical conditions, the CO2 behaves similar to solvents similar to hydrocarbon extracts like hexane in terms of its solubility selectivity. This higher solubility means a highly efficient extraction of desired cannabinoids. Raising the pressure and temperature of the liquid CO2 further provides extraordinarily powerful extractions of oils in a shorter period of time.
- After the separation of desirable cannabinoids, the CO2 is reverted back into a gaseous state leaving a “crude oil” comprising CBD or THC, terpenes and residual plant materials ready for distillation and product formulation.
Other Frequent Extraction Processes:
Though CO2 extraction is likely the most efficient, safe, and healthy choice for cannabinoid extraction, producers are always looking for the next cutting edge extraction method for their business. Because of this, there are various other extraction processes that have become widely popular, but are questionable in their efficacy and their safety:
Extraction accomplished via hydrocarbon solvents is effective, but not completely safe for manufacturers or consumers. During extraction, it’s essential to remember that common solvents within this category are hexane, propane and butane — all of which are very volatile. This poses a heightened risk for fire and explosions. That comes increased costs for blast-ready rooms, infrared gas sensors and C1D1 specifications that contribute to general operational costs.
While the majority of those hydrocarbons are taken out of an extract during solvent elimination in terms of consumption, it is not guaranteed that the entirety of those byproducts will be taken off. This means that consumers are facing the choice of consuming a hemp or cannabis extract containing parts-per-million (PPM) of those solvents. There is minimal research to suppose that continued, daily usage of those products will have no long-term health effects over the course of a customer’s life.
Ethanol extraction has become relatively common in the extraction industry as well. This method uses some form of alcohol, such as food grade ethanol, as an extraction solvent to provide high quality extracts. This method is very efficient on a production scale though it is somewhat dangerous to work with as it is flammable.
The issue, however, comes from the most typical form used for extraction: denatured ethanol. Where food grade ethanol is a very safe option (grain alcohol for instance) it is much too costly for any sustainable business model. Therefore, manufacturers turn to denatured ethanol which is Generally Regarded As Safe (GRAS) by the FDA. However, denatured ethanol comprises chemical denaturants used to deter recreational consumption so that it can be marketed as gasoline, cleaners and other products without paying beverage taxation.
Much like hydrocarbon extraction, solvent removal removes a significant sum of the ethanol left over in the extraction process, but it’s never ensured that all of the ethanol is removed. In fact, the FDA permits for certain PPM of pentane, methanol, hexane and other denaturants in extracts which are still considered “safe” for ingestion. It’s unknown whether daily consumption of residuals could have lasting negative effects on the entire body.
Supercritical CO2 Extraction
Incredibly efficient in its supercritical condition, CO2 is a quick, clean, low-cost extraction solvent that is tried and true. For manufacturers, CO2 may be used for drastically lower costs than ethanol or hydrocarbon extraction concurrently eliminating prices for blast ready facilities due to absence of flammability. Since it’s natural, it also allows for obtaining organic certification and reduces harmful emissions that are harmful to the environment.
Though efficiency is often top of mind for most producers, customer satisfaction and safety should be paramount. Those producers that use CO2 will declare it proudly on their product labeling and their content as a testament to the care they have for their customers. After all, the health of the consumer means the continued use of the product which is why consumers of CBD and other cannabis products need to always understand how their product was extracted.
In short, CO2 extraction, ethanol extraction and hydrocarbon extraction can create desirable CBD extracts; however, CO2 extraction has an edge over ethanol and hydrocarbon extraction as a result of clean, high throughput efficiency and the avoidance of risk related to chemical contaminants. CO2 extraction can also be much more affordable than other extraction solvents. For those reasons CO2 is a far better extraction procedure in the hemp and cannabis industry.
Jon Thompson, PhD, is a separations scientist and CEO of extraktLAB, an accredited engineering company for extraction, distillation and product formulation in the CBD, hemp and cannabis industries.