Industry & Investment

Safe and Effective CO2 Extraction Methods

December 19, 2017 / By 3C Team

As more and more cannabis consumers are purchasing extracts, processors are continuously striving for better and safer extraction methods. While various extraction methods still exist, the current winner seems to be supercritical CO2 extraction for cannabis products.

What Is Supercritical CO2 Extraction?

Supercritical CO2 extraction involves using controlled temperature and pressure to create phase (or state of matter) changes in CO2 (carbon dioxide) for the purpose of extracting cannabis plant material while maintaining the integrity and amounts of terpenes found in the plant material. At the same time, it protects cannabinoids from decarboxylation during the extraction process. The phase changes (for example, from gas to liquid) in CO2 allow you to separate out plant material of different weights during the extraction process.

cannabis extract

Why Use Supercritical CO2 in Cannabis Extraction?

Supercritical carbon dioxide (sCO2) is a variable state of carbon dioxide where it is held at or above it’s liquid-vapor critical point (the maximum temperature and pressure at which a substance can coexist as both a liquid and vapor in equilibrium). According to scientists at Perdue University, CO2 has a critical temperature of approximately 88 degrees fahrenheit and a critical pressure of approximately 1,073 psi (pounds per square inch). When placed under pressure above 1,073 psi, CO2 becomes what is called a “supercritical fluid.”

In this state, supercritical fluids (SCFs) possess densities like liquids, viscosities like gas and diffusities somewhere in between that of a liquid and a gas. In other words, supercritical CO2 expands to fill its container like it would if it were in the form of a gas, but with the density of a liquid. This CO2 supercritical fluid is used to remove essential oils from cannabis plants (or any other plants for that matter) without leaving any residues behind. Supercritical CO2 is cleaner and greener than many other solvents so it’s better for both the consumer and our planet. This is a reason that socially-conscious cannabis extractors choose to use CO2 supercritical fluid.

Frequently used in commercial cannabis extraction labs, CO2 is a “tunable solvent” (meaning its solvation strength can be tuned incrementally by making slight adjustments to the density of the CO2 supercritical fluid). Supercritical CO2 extraction is hands down the safest and cleanest method of commercially extracting cannabis oil from your plants and it can be used to create a variety of end products.

Advantages of Using CO2 as a Solvent

There are many pros to using CO2 as a solvent in the cannabis extraction process.

Compared to conventional solvents, CO2 is relatively inexpensive, non-toxic, non-flammable and inert (chemically inactive). It also has the distinct advantage of being able to diffuse through cannabis plant material like a gas, and to dissolve plant material like a liquid. In addition, CO2 leaves less residue upon being used in the extraction process compared to solvents such as butane. Finally, CO2 is easy to obtain and is readily available in virtually pure form.

How Is Supercritical CO2 Extraction Superior?

Supercritical CO2 extraction is currently the “gold standard” of cannabis extraction methods because it’s cleaner, more efficient and safer than other methods of extraction. Butane extraction, for example, can leave traces of heavy metals. By comparison, supercritical CO2 extraction yields cannabis oils, waxes and rosins with the highest purity level and no residual solvents. In addition, even though CO2 is a greenhouse gas (a contributor to global warming), when it is removed from the environment, used in an extraction process, and expelled back into the environment, it does not result in any increase in greenhouse gas emissions.

Another advantage of supercritical CO2 extraction is the fact that it enables you to separate individual compounds during the extraction process. Large-scale commercial plants using supercritical CO2 extraction are also commonly found in the food industries. Fun fact: Coffee decaffeination uses supercritical CO2 extraction equipment to separate caffeine from coffee.

Measuring Effectiveness of the Extraction Process

In measuring the effectiveness of any extraction method, overall yield is actually less relevant.

Yield data is often gathered as it can be helpful in establishing a baseline for a financial model, determining ROI, etc. However, the yield of any extraction process depends upon the quality of the original source material. The cannabinoid content of different strains of cannabis varies greatly, not just between indica and sativa, but within each category there are unique cannabinoid profiles. Generally plants are bred specifically to produce high levels of THC or to be CBD dominant but of course there are many hybrids as well. The amount of total THC extracted compared to the amount present in the feedstock provides the best measure of extraction efficiency.

What Are Full Spectrum Extracts?

Full spectrum extracts provide a more comprehensive experience in terms of flavor and effects. These extracts take much more sophisticated technology and expertise to produce and will be highly valued moving forward. For full-spectrum extracts you would compare the THC, cannabinoid and terpene profiles of the feedstock with the extract not only for efficiency but also the balance in chemical makeup.

Cannabis plants are made up of a complex combination of chemical compounds that dictate the effects, taste and smell of the flowers. In their whole form, cannabis flowers are made up of hundreds of cannabinoids, terpenes and other molecules. Without thorough training in organic chemistry many extractors don’t completely understand the intricate processes involved in creating a quality extract. Therefore they mistakenly continue to refine and purify their extracts to remove contaminants. Extract that is 95% pure THC means that the extractor essentially diminished much of the medicine of the whole plant. You might say that vaporizing extract that is 95% pure THC is the equivalent of eating processed food as opposed to drinking cold pressed juice.

Are you planning to open a cannabis extraction facility? If so, we’re here to help. 3C cannabis consultants will ensure that you are using the safest and most effective extraction equipment available. We will also help you to meet city, state and federal safety regulations to ensure that you are operating your business in compliance. If “Safety First” is your top priority, your extraction facility will be in business for many years to come.

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