The process of supercritical CO2 extraction for CBD
What is Co2 extraction?
Carbon dioxide (CO2) extraction is a safe, non-toxic, environmentally-friendly process of extracting desired compounds from botanical sources.
A relatively new way of processing hemp to obtain its cannabinoid-rich resin, the Co2 extraction method is widely spread among other industries.
A few examples where co2 extraction is used for:
- removing caffeine from coffee beans,
- removing nicotine from tobacco,
- essential oil production,
- hop extraction for beer production
CO2 is also used for:
- carbonation of beverages
- dry cleaning
- fire extinguishers
Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms. It occurs naturally in Earth’s atmosphere as a trace gas and is always present in the human body. It is considered harmless and also essential for us to function.
At room temperature, carbon dioxide is a colorless and odorless gas. But to perform extractions with carbon dioxide, we need to change its state of aggregation. If we are freezing CO2 below -78°C we obtain carbon dioxide in a solid-state (Dry ice) which also has some uses in hemp processing.
On the other hand by heating carbon dioxide, we can convert it to a liquid state, or even better to a supercritical state. This is achieved by heating CO2 above 31.10C (critical temperature) while maintaining it under the pressure of 74 bar (critical pressure) to become a supercritical fluid.
In this supercritical form, CO2 has both the properties of a gas and a liquid, becoming the perfect solvent for hemp extraction.
For Co2 extracted Essential Oils from sources other than hemp, please click here.
What is Supercritical CO2 Extraction?
To perform a supercritical CO2 extraction we need to put CO2 in said parameters. Special equipment is needed to maintain CO2 in these conditions.
The Supercritical CO2 extraction systems need to be engineered appropriately to resist such temperatures and pressures.
A CBD extraction machine is made out of stainless steel (a standard in food and pharma industry) and usually consists of:
- A Chiller
- An extraction vessel
- Collection vessels
- CO2 tanks
- Pipes, gauges, valves, pumps
- Control panel
The CBD extraction machines are also closed-loop systems, so the CO2 gets recycled back to CO2 tanks and can be reused for future extractions.
A quick overview of the CO2 hemp extraction process is as follows:
- The extraction vessel is filled with hemp. The hemp biomass should be free of water and finely ground for optimal volume efficiency.
- Pressurized CO2 (in the supercritical state) passes through the extraction vessel to interact with hemp, extracting various compounds present in hemp such as cannabinoids, terpenes, and flavonoids among others.
- Supercritical CO2 then carries the hemp extract to the collection vessels
- In collection vessels, the pressures are lower than the supercritical range, which transforms CO2 back into a gas form and allows it to be recollected into CO2 tanks.
- As CO2 becomes a gas, its solvent properties are gone and the hemp extract separates from CO2.
- At different pressure and temperatures, different fractions of hemp resin are extracted in the collection vessels.
- These fractions either represent more volatile substances like aromatic terpenes and towards the other side of the spectrum, heavier oils and waxes containing cannabinoids like CBD.
Crude hemp extracts are usually full of waxes, lipids, chlorophyll, and other compounds. There are some users who prefer this kind of unrefined oil. But usually, additional post-processing is required to satisfy most users.
More advanced CO2 hemp extraction machines, like our MoSES system, allow fractionating during the extraction. By modulating temperature, pressure, and extraction time, we can separate and discard some unwanted compounds like waxes while targeting desired compounds like CBD. This way we save a lot of time and labor on post-processing techniques like winterization, color remediation, decarboxylation…
With the possibility of collecting different fractions, we can obtain CO2-SE (selective) and the CO2-TO (total) extracts when extracting different medicinal plants, spices, and herbs.
Why do we use CO2 extraction for CBD/hemp extraction?
There are many methods of stripping the CBD from the hemp plant. Some are mechanical, some use solvents, some involve advanced technologies such as microwaves and ultrasonic sound.
But all of them aim for the same goal, to capture the essence of the plant. At the end of the day, it is not always a matter of quality, why a specific extraction process is chosen. It boils down to many different factors, such as equipment cost, time efficiency, extraction yields, skills required for the operation…
But for us, the first and most important thing IS quality. We make no compromises with that. Even if the CO2 extraction system is a bigger investment, the cost of maintenance is higher and it requires a qualified operator.
The benefits of CO2 extraction for the best quality CBD extracts
We believe that supercritical fluid extraction is superior in every aspect.
Almost 100% of cannabinoid extraction efficiency is one of the main benefits of CO2 hemp extraction. In CO2 extraction essential oils, the terpene retention is also impressive.
By using food-grade CO2, the final extract contains NO residual solvents which might be harmful to the consumer. With supercritical CO2 hemp extractions, we require no additional steps of solvent purging, so our extracts retain more of their original form.
Most unwanted compounds like waxes or chlorophyll can also be filtered out during the extraction process. This way we again avoid unnecessary manipulations of the hemp extract which might alter its natural chemical composition.
Relying on supercritical CO2 hemp extraction, we can obtain an organic CO2 extract rich in cannabinoids and free of impurities. And this is what matters the most, to put on market something we are proud of, something that cannot be any better.
If you would like to know more about our MoSES supercritical CO2 extraction system or if we got you interested in hemp extraction, do not hesitate to contact us regarding any questions or concerns you might have. If you would like to try CBD, check our wide range of products with different ways of application. We are sure you will find something for yourself!