Updated: Apr 13
In this blog post, we will discuss the benefits of R134a Extraction Methods versus CO2 for cannabis extraction. If you're ever in the San Diego metro area and would like an in person tour of our facilities, you can contact us here to set that up; we'd love to show you the future of the industry.
PurBlend Science employs a Liquefied Gas Extraction (LGE) Technology platform that was initially created in 2004 to support food, pharmacy, and perfumery product manufacturing. Here at PurBlend Science, we refer to this technology as the PBX STANDARD (Pure Botanical Extraction), in recognition of the technology’s process and pure outputs.
Post-winterized full-spectrum oils
One method of cannabis extraction utilizes tetrafluoroethane (TFE) R134a as a solvent. R134a is often used in aerosol products for drug delivery. Products that are extracted using this methodology are called 'post-winterized full-spectrum oils' considering the amount of waxes in the extract right off the machine is usually less than 5%. The R134a extraction process is very similar to CO2 extraction due to the fact that both methods utilize a gas for extraction, and liquefy it when it is in contact with the material.
The cannabis extraction process with R134a is performed at low pressure and room temperature in order to strip the natural oils from the raw cannabis products in a closed-loop system. The gas is slightly pressurized, then driven through the plant material and recovered in a separation tank leaving the full spectrum oil behind. R134a is safe for human health – nontoxic, FDA approved and qualified as GRAS (Generally Recognized As Safe). European Union approved the usage of the gas as solvent by EC Directive 2009/32.
The small non-polar molecule size and the inert nature of the R134a solvent penetrates the plant tissue extremely well and thoroughly extracts the oil-soluble fractions. R134a extraction is performed at room temperature conditions and the extraction process is neutral to the plant’s full spectrum oil.
The full terpene profile is collected without degradation of the plant’s components and is easily separated from the solvent. This is why extraction is most often done on “fresh flower” as well. R134a does not extract solids, and in most cases, winterization is not required. Furthermore, the PBX STANDARD (Pure Botanical Extraction) process does not transfer water-soluble compounds like chlorophyl or mold to the extract thus providing a very pure process for extracting plant oils.
One of the most popular methods of cannabis extraction is via CO2 as a solvent. This method uses the advantage of the supercritical properties of CO2 gas to strip materials from botanical substances. This method for extraction has been used by a variety of industries before it was applied to cannabis, like perfumes and essential oils, although the cannabinoids have quite a different structure than essential oils, and they cannot be extracted together. That is why extracting the cannabis oils with CO2 is done through running supercritical extraction, and the terpenes by running subcritical extraction, thus resulting in an extremely long processing time.
CO2 is a low density gas and needs to be pressurized to about 600 atmospheres (8817 psi) to become a solvent for essential oils, for example. As a result of these extreme pressures, operating temperatures and the process architecture, scaling the CO2 system and required operation is an expensive process.
CO2 extraction cannot extract moist material very well as the moisture and CO2 connection brings up undesired acidity levels in the extract. This results in a less than favorable extract in which a plant’s full terpene profile is desired.
Unlike CO2, R134a is inert, odorless, non-toxic, non-flammable, non-corrosive and does not form an acid in the presence of moisture. This widens the scope of applications to include many pharmaceutical products that are pH-sensitive.
It is very important to know that the room temperature of extraction means no thermal degradation or loss of volatile compounds during isolation. A low boiling point of R134a eliminates the need for complex and slow solvent recovery.
CO2 extraction requires special training and expensive equipment. In contrast, R134a is easy to operate, does not require a science degree and operates with extremely high consistency on the output oil. CO2 requires a high CAPEX as you may run several systems, and an army of technicians. This is costly, compared to R134a, with very low cost of maintenance and workforce.