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Bringing Sexy Back to Supercritical CO2 Extraction

Published: Aug 24, 2021   

Image credit: Green Mill Supercritical

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In a 2017 description of supercritical CO2 extraction, Pittsburgh-based chemical engineer and professor Robert M Enick, PhD, waxed poetic with childlike wonder on the solvent’s power and potential. His three-minute explanation contrasts CO2 with other solvents, praising the substance for its “almost magical” transformative capabilities and multiple applications. By any account, it is a glowing endorsement.

And so it has been since the earliest days of cannabis legalization, when proponents heralded supercritical CO2 as the industry’s most versatile extraction solution while detractors derided its equipment expense and technical complexity. But the innovative laboratory atmosphere created by the scientific and technical possibilities of CO2’s dynamic density properties made supercritical CO2 exciting and sexy in those fast-moving early days of the legal industry. Over time, though, even an inferno can cool down to an ember, and as infused products, concentrates, and other oil-based products proliferated, the excitement and sheen of supercritical CO2 took a back seat to the growing popularity of the products it helps to produce.

While its luster has never waned among supporters, supercritical CO2 became just another tool for cannabusiness to pursue an increasingly commoditized infused products market. Innovation took a back seat to sales and expensive workarounds to resolve critical issues became the accepted and inevitable norm. It seemed as though extraction machine manufacturers collectively decided that this technology had developed as far as it could go, and the industry settled into a decidedly un-sexy period of status quo normality. Today, however, a new focus on innovation has arisen. New technologies and methods are being researched and developed. An increased pace of competition has taken hold among CO2 proponents, and debates over approaches are thrusting CO2 extraction into the limelight once again. 

Jeremy Diehl, co-founder and CTO, Green Mill Supercritical. 

What’s driving the revolution?

Today, the cannabis industry sits at a crossroads. Its initial status as an excitable infant and adolescent is transforming into that of a young adult still searching for itself but ready to explore new horizons. This evolution is driving change across the industry, particularly among extraction machine manufacturers, where a new generation is addressing the key challenges facing the growing concentrates and infused products industry.

Projected growth: As new legalized markets open and the popularity of cannabis products continues to grow, managing extraction costs at scale will become an increasing concern for processors.   Identifying ways to reduce expenses, maximize production and generate purer and more potent oils and concentrates will propel businesses forward and determine which ones will survive and thrive, and which ones will fall by the wayside. If there is an overriding rationale for the need for innovation in CO2 extraction, the projected growth of the market is it. Almost no one believes that current costs associated with secondary extraction processes and post-production expenses can support the growth that will be necessary to meet increasing product demand. 

Maturation of consumer preferences: Consumer tastes continue to evolve as different types of infused products enter the market and customers move from novice cannabis users to seasoned enthusiasts. As their tastes mature, these consumers are increasingly seeking a more refined experience from their cannabis products, with a growing focus on specialized terpene profiles and a desire to enjoy the “full essence” of the plant. Typically, products providing these more robust and enhanced effects can fetch increasingly higher prices as “premium” or specialty products geared toward a more sophisticated consumer palate. But an ability to create the oil needed to develop these high-end products is entirely dependent on extraction capabilities that can meet the challenge. Without innovation and ingenuity in CO2 extraction, it is highly unlikely that these premium products could exist, much less be cost-effective for producers to create. 

Lack of innovation: The long-standing processes that have become the norm in CO2 extraction are being called into question by extraction machine manufacturers who dare to challenge the status quo. In the market today, supercritical CO2 equipment extracts, for the most part, are crude oil typically refined using a separate, complicated and costly process of ethanol-based winterization. But recently announced CO2 extraction innovations (including Green Mill Supercritical’s Real-Time Winterization) focus on ways to streamline or otherwise improve the winterization process. In the case of Green Mill’s efforts, we are eschewing the use of ethanol entirely and attempting to push the preconceived limits of CO2 that others continue to adhere to out of a lack of ingenuity.

As a result of these factors, several of the major players in the CO2 extraction equipment space for cannabis have announced upgrades to their product lines, and the competitive battle lines have been drawn. But when examined up close, it is easy to uncover that what is often marketed as innovation is actually a self-defeating shortcut that cancels out the very qualities of CO2 that make it advantageous in the first place. For instance, the use of a co-solvent such as ethanol or butane to boost the speed of an extraction creates the illusion of improved throughput, yet it comes with three huge caveats:

  1. It adds to the amount of post-extraction processing required.
  2. It kills the key advantage of CO2, which is its tunability.
  3. It fundamentally alters the structure of your business if what you had built was based on CO2.

Today’s seasoned and educated extract consumer, whether medical or recreational, demands the effects, flavors and aromas indicative of the original plant, and that means capturing the terpenes and other compounds native to the source material. To create a high purity, full spectrum extract that is indicative of the starting material requires new thinking and a new approach. Some in the industry continue to default to the use of ethanol for winterization, and even, as mentioned above, resort to using it as a co-solvent to try to gain throughput efficiency, but this serves only as a betrayal to the nearly limitless promise of CO2. To fully embrace those possibilities, extraction professionals must put their trust in the compound. There’s a reason so many have chosen supercritical COas their preferred extraction method. 

As the cannabis and hemp industries expand, demand for extraction technology continues to grow. The growth in popularity of CBD, as well as infused cannabis products and extracts, ensures an ongoing need for extraction machines with new capabilities and cost-saving features. Meanwhile, other botanical-based products are also generating consumer interest, and now growing excitement about psilocybin mushroom extraction for medical and recreational use is gaining ground.

Clearly, supercritical COextraction is a technology on the rise and the need for innovation has never been greater. It is an exciting time to be working on the challenges facing the market and there is no doubt that CO2 extraction is indeed sexy once again. 


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