Supercritical CO2 Extraction: A New Standard In Cannabis Processing?

Flower dominates the cannabis market, but sales of concentrates, edibles and topicals are seeing impressive growth and quickly catching up.

Sales of concentrates in Colorado, Oregon, California and Arizona amounted to $1.26 billion in the first nine months of 2018, according to BDS Analytics estimates.

For companies to create concentrates, edibles and topicals, they must process cannabis in order to extract tetrahydrocannabiol (THC) and cannabidiol (CBD).

How Cannabis Can Be Processed

With the cannabis industry in a transformational phase, the number of processing methods has seen massive growth. 

Generally, cannabis extraction processes are grouped by whether they are solventless or solvent-based.

Solventless methods, such as dry-sieve and water extraction, are natural, but don’t yield the same results as processes using a solvent. On the other hand, extraction using solvents provide a better percentage of CBD and THC but might have some drawbacks.

Many companies have been using supercritical CO2 extraction for cannabis. We decided to take a closer look at the process. 

What Is Supercritical CO2 Extraction?

Supercritical CO2 extraction has been around for decades in a variety of other industries before cannabis such as coffee, tea, vanilla and perfumery. It works by creating supercritical carbon dioxide, which retains features of both gases and liquids. CO2 is captured and pressured while simultaneously being cooled to turn it into a liquid.

The liquid CO2 is then heated and pressure is increased to reach a supercritical state. In this state, the CO2 occupies an entire space like a gas, but also maintains the same density as a liquid.

When passed through cannabis, supercritical CO2 is passed through cannabis and extracts all waxes, trichomes and terpene oils from the plant mass. The solution is then passed through a separator, where it is broken down into its components. The CO2 is then brought back to a liquid state and can be used again. Any remaining CO2 in the extracted material is turned into a gas once the pressure drops back to normal.

“The main benefit of SCO2 is that it enables the extraction of more total cannabinoids along with other plant components like fats and waxes. This method works well for products that require further post-processing like distillate oil,” Mylad Piroozbakht, manager of extraction and formulation at Sunniva Inc SNNVF, told Benzinga.

Benefits of SCO2 Extraction

In addition to allowing the extraction of more cannabinoids and other components of the cannabis plant, the supercritical CO2 extraction process is also lauded for a number of other benefits.

One of them is environmental friendliness. Compared to other solvents, supercritical CO2 doesn’t have any effect on the environment. It’s non-toxic, non-flamable, renewable and abundant.

This provides companies with a number of benefits. Since supercritical CO2 extraction is safer compared to some other methods, such as butane or ethanol, it’s easier for companies to comply with facility rules and regulations.

It’s particularly important for companies with operations in multiple states and countries, as Joel Sherlock, chairman and co-founder of Vitalis Extraction Technology, points out.

" ... Regulations vary jurisdiction to jurisdiction [and] ethanol and hydrocarbons are combustible solvents and traditionally require varying degrees of customization, explosion proof walls, floor venting and fire suppression,” he told Benzinga. 

In this way, using supercritical CO2 provides companies with an advantage, “as they can have the same machine in every location,” Sherlock said. 

How It Compares To Other Methods

Despite the benefits of supercritical CO2 extraction, other technologies are also widely used. One in particular is ethanol extraction. Ethanol is more efficient and safer to handle compared to supercritical CO2, which requires high-pressure systems.

“With ethanol vs. C02, we’re seeing similar results — while ethanol is more efficient, effective, safe to handle and has a relatively low environmental footprint, it is perhaps not ideal for high-volume production,” said Keith Merker, CEO of WeedMD Inc WDDMF.

Shea Alderete, CEO of GenX BioTech, said ethanol extraction can also give better results because it allows for a broader range of molecules to be extracted. 

Compared to butane, supercritical CO2 has the advantage of being safer. Yet butane wins a lot in terms of costs. CO2 systems range between $150,000 and $200,000 on the low end, while butane systems are between $20,000 and $60,000, Alderete said. 

What The Future Holds

As technology advances, the kinks in each system are likely to be worked out in order to improve efficiency and provide better quality products no matter what extraction method is used. 

New extraction technologies are likely to come online as well. Some results of R&D programs are already visible.

One example is the aqueous phytorecovery process, which recovers water-soluble whole-plant biomolecules — including cannabinoids and terpenes — followed by free oils from the plant tissues.

“The method produces all-natural plant extracts that can be further fractionated to obtain pure species of individual molecules. The water soluble preparations display full-spectrum, plant-specific biomolecules and also have fast onset and fast offset effects on the consumer; these preparations are ideal for use in water-based beverages with or without other nutrients in pleasant-tasting beverages,” said Dr. Arup Sen, the CSO of Sproutly.

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