From Extracting to Refining
“For some customers, producing oils that have 0.0% THC content is important.” — Andrew Defries, PhD
CO2 is a “tunable solvent,” making it extremely versatile for creating many end products. Simply by increasing or decreasing pressures and/or temperatures in our 90-liter extractor, the solvency power of CO2 can be adjusted to selectively extract different constituents. Unique extractions can be created that have varying levels of desirable oils and waxes. Similarly, less desirable plant constituents such as chlorophyll can be eliminated.
SUBCRITICAL EXTRACTION. In subcritical extraction, during which temperatures are kept below 87.98 F and pressure below 1073 psi, the carbon dioxide remains in a liquid state. The lower temperature and pressure result in very different cannabis product from that resulting from supercritical extraction.
The subcritical product preserves cannabinoids other than CBD. Subcritical solvents are of interest when extracting yields with increased volumes of terpenoids, flavonoids, and other such volatiles. Subcritical carbon dioxide runs at milder extraction parameters than other solvents, targeting these volatile compounds. At subcritical parameters, it is possible to remove extractants that are thermolabile, resulting in more aromatic extracts. Extracts obtained from CO2 most closely resemble the natural starting material, which is the goal of essential oil extraction.
If you follow a subcritical run with a supercritical extraction to completely scrub the matrix of any remaining valuable compounds, a full-spectrum extraction is achieved.
SUBCRITICAL ADVANTAGES. The subcritical product preserves cannabinoids other than CBD. Subcritical solvents are of interest when extracting yields with increased volumes of terpenoids, flavonoids, and other such volatiles. Subcritical carbon dioxide runs at milder extraction parameters than other solvents, targeting those volatile compounds. At subcritical parameters it is possible to remove extractants that are thermolabile, resulting in more aromatic extracts. Extracts obtained from CO2 most closely resemble the natural starting material, which is the goal of essential oil extraction.
SUPERCRITICAL EXTRACTION. Supercritical carbon dioxide is a fluid form of carbon dioxide obtained where it is held at or above its critical temperature and critical pressure (87.98 F and 1073 psi, respectively). By changing extraction pressure and temperature, the solvent power and selectivity of supercritical CO2 can be changed to optimize an extraction for a species of interest.
Supercritical liquids can pass through porous solids and also dissolve materials, making them ideal as a solvent. By changing extraction pressure and temperature, the solvent power and selectivity of supercritical CO2 can be changed to optimize an extraction for a species of interest. This “tunability” of supercritical CO2 extraction enables targeting maximum outputs of cannabidiol depending on the type and quality of cannabis material being used, while keeping undesirable compounds such as chlorophyll out of the product.
When used without fractionation built into the process, supercritical systems produce a substance made up of fats, oils and waxes that has the consistency of peanut butter. A process called “winterization” may then be used to remove the fats and waxes, leaving just the CBD oil. Using a fractional extraction approach, lower temperature and lower pressure can be used to extract an oil suitable for applications such as vaping. Then, by raising the temperature and pressure, the heavier compounds can be extracted. This approach extracts the most from the same amount of trim material and requires less additional processing.
SUPERCRITICAL ADVANTAGES. While the ScCO2 process may destroy various cannabinoids through thermal degradation, it yields more cannabidiol in a far shorter time than does subcritical CO2 extraction. Supercritical oil extraction also kills off bacteria, mold, and other forms of contaminants that could prove problematic for people with already compromised immune systems. Another advantage of using a supercritical system is that it can be used for subcritical uses as well whereas vice-versa isn’t possible.
CANNABIDIOL OIL YIELDS WITH SUPERCRITICAL CO2. Very generally speaking, the ScCO2 method of extraction will produce around 10% “true” cannabis oil based on trim weight; however, if you add in the resins and waxes that may be desired in some applications, yields may be anywhere from 17-25% of product.
WHICH IS BEST – SUPERCRITICAL OR SUBCRITICAL? It really depends on the application as to whether supercritical or subcritical extraction is the best choice. However, a system such as the Vitalis 90-liter Q-series CO2 extractor capable of working at supercritical temperatures and pressures provides the most flexibility.
Post Processing and Refinement
Our post-extraction laboratory is equipped to produce pure CBD isolate and distillate oils. For some customers, producing oils that have 0.0% THC content is important. The process of winterization alone does not eliminate THC. Safe elimination of THC requires extensive post processing in a safe and properly equipped laboratory such as ours.
Our extraction and refining protocols are being developed by our on-site consultants Andrew Defries and Wayne Karim. Andrew has a PhD in Chemical Genetics and an interdisciplinary skill set. He has been Director of Quality Control at TIKUN OLAM USA, the American division of the leading cannabis company in the world. Wayne has been Director of Extraction for TIKUN OLAM USA. Andrew and Wayne will ensure that our customers’ material undergoes the best treatment possible.
WINTERIZATION. Winterization involves mixing the substance with ethanol (alcohol) and placing it in a freezer for around 24 hours, which crystallizes the fats and waxes. The deeply chilled liquid is then run through a filter, leaving the fats and waxes behind on the filter paper. The filtered ethanol mixture is then evaporated (reclaiming the ethanol in the process), leaving pure and cannabidiol-rich cannabis oil.
Analysis and Testing
HPLC. Our High Pressure Liquid Chromatography (HPLC) testing platform could be the most important service that we offer customers. The HPLC is used to determine the content of the plant material and also to verify the content of the finished CBD oil and other end products. Third party testing will also be used to confirm the accuracy of the testing.
The HPLC will be an asset for controlling risk factors associated with cultivating industrial hemp. As crops mature, cannabinoid content increases. HPLC testing equipment will ensure that plants do not produce cannabinoids beyond the state regulated limits.