Almost all the CBD products that are available in the market are made using a CBD extract. The quality of the extract is primarily determined by the extraction process used to produce it from the hemp plant. There are different extraction methods used, but CO2 extraction is more widely used because of the highly pure end product. All the high-quality products use this method and it will be reflected in the price. So what is CO2 extraction of CBD?
There are two types of extraction namely: supercritical CO2 extraction and subcritical CO2 extraction. Because of the purity of the end product, they have become the preferred method used to produce medical and therapeutic CBD or hemp products. The compounds in the hemp plant are extracted using a solvent and in this method, they use subcritical or supercritical carbon dioxide. This is because it is environment-friendly, cheap, less toxic, cleaner than fossil fuel based solvents. So, CO2 hemp extract is purer and of the highest quality.
Now let us understand in detail about the two types of CO2 extraction methods.
Supercritical CO2 Extraction
At standard or normal room temperature, carbon dioxide is a gas. But, when you decrease the temperature to -78.5o C at standard pressure it becomes solid or dry ice. If you increase the pressure to 60.4psi it becomes liquid. Now, if you heat it to the critical temperature of 31.10oC and increase the pressure to the critical value of 1,071psi or higher it will attain the properties of both gas and fluid. Such a liquid is said to be in a supercritical state. It can pass through porous materials as well as dissolve substances making it an ideal solvent. Besides, you can fine-tune its solvation capability by adjusting the pressure to extract the maximum number of compounds.
In this process, the extracting chamber is filled with the hemp plant materials and a pump forces supercritical CO2 into the chamber. The solvent absorbs the phytocannabinoids and this mixture is transferred into a cyclonic separator. Here the pressure is reduced and carbon dioxide and CBD oil separate. The gas is reabsorbed and the oil, waxes, resins are accumulated in a collection vessel; this residue is purified further to produce CBD rich extract.
Subcritical CO2 Extraction
In the subcritical CO2 extraction process, carbon dioxide is below the critical temperature and it remains in a liquid state. The difference from the previous method is that here it preserves cannabinoids other than CBD and it may or may not be desirable. The yield is lower than supercritical CO2 extraction and takes a longer time as well.
Therefore, the choice between supercritical and subcritical CO2 extraction process depends on the type of final hemp CBD extract required.