25 Apr Supercritical CO2 Extraction Process: How to Use CO2 to Make Extracts
Supercritical CO2 extraction has been said to be the cleanest way to make solvent extracted concentrates, and the scientists at extraktLAB® are working to simplify this process for you.
What is Supercritical CO2 Extraction?
Supercritical CO2 extraction has been used for decades to make essential oils from all kinds of botanical plant materials and has been most commonly used in industrial settings to extract specific components. In the past decade, the technique has become a popular method to extract resin, waxes, and actives from botanical matter.
Advantages of CO2 vs. Other Solvents
One of the key advantages to using CO2 over other nonpolar solvents is that pressurized CO2 is inert and is not flammable. The extraction can take place, and then the CO2 will just evaporate from the extracted resin upon exposure to lower pressures to leave clean, oil-free, residual solvents. Best of all, CO2 oils are versatile and can be used to create a variety of end-user products.
The Extraction Process
The supercritical CO2 extraction process starts 6-9 months before an actual extraction takes place. First, the cultivation experts select the genetics to plant. Having cannabinoid assays and wax content data on the strains go a long way to help estimate the extraction yield and production output. Second, the plant is harvested, dried, and then ground so that it can be extracted. Typically, sticks, roots, and fan leaf are not extracted and are discarded from the process simply because they have little to no active product within them. The plant material is then loaded into the extractor to separate the oils from the plant material.
Using Trim as the Main Extraction Source
Some extractors use trim exclusively as the source material for their extractions. Trim is derived from the trichrome rich, outer leaves that encompass the flower. The overall cannabinoid content of these leaves can range from 10-15%, and high-grade trim usually includes small flowers that cannot be sold elsewhere. Quality trim can be obtained from a variety of producers at a wide range of quality. In our experience, there is no difference in quality between outdoor and indoor trim. However, some less scrupulous purveyors sell their fan leaf and stems containing 1-5% cannabinoids at a reduced cost per pound. This trim is actually waste material that can contain high concentrations of pesticides and/or herbicides. Care should be taken when purchasing trim since the cost to produce a gram from poor quality trim is greater than the cost to produce from high-quality trim.
How Supercritical CO2 Extracts Oil
Once the plant matter has been ground, it is placed in the extractor. Cannabinoids and other plant components that are soluble in CO2 are then dissolved in the supercritical CO2 and are conveyed away from the plant matter underflow. The rate at which the active dissolves depends on the pressure and the temperature of the mobile CO2 fluid. Higher pressures and temperatures increase the solubility of the actives dramatically but also can dissolve undesirable components such as chlorophyll. Once the oil is conveyed away from the insoluble plant material, the solution enters a downstream vessel where the solubilized cannabinoid and wax crashes out of the solution. This process creates an extract with minute amounts of residual CO2 left over.
The oil is then collected in a containment system and is subsequently warmed in a water bath to give a viscous waxy oil. Potency coming right out of the Extrakt-1 machine is typically around 70-80% and winterization of that oil improves the potency even more. Winterization is just a non-technical term for removing the waxes from the extract by placing a bottle of extract dissolved in ethanol in the freezer and subsequently removing the waxes with a DrainDroyd. Typical potencies of dewaxed oil exceed 80% and are typically around 85-90%.
extraktLAB® Makes Supercritical CO2 Extraction Easy
The supercritical CO2 extraction process is made easier using our production methods including igwLAB integrated workstations, which are a manufacturing execution system, and also using an Extrakt-1 CO2 extractor with built-in, easy to use methods. Standard recipes come built into the equipment, so you don’t necessarily need to worry about the specifics. Of course, you can run any recipe as desired, but the standard methods give you a good starting point.
The key advantages of the Extrakt-1 extractor are that it is fast, has little carryover, has a containment system, and is integrated into igwLAB’s MES (manufacturing execution system) with no need for custom API or further integration. The system offers high-pressure vessels for extraction, collection, and recycling. Reproducibility, throughput, and efficiency problems that many CO2 extractors face have been solved by extraktLAB®. Finding solutions for these issues can make the process easier to replicate and safer for the consumer. These solutions can also help make the extraction laboratory a lucrative business endeavor.