The basics of CO2 cannabis extraction

The quality of cannabis extracts depends not only on the quality of the plant, but also on the extraction technique used. Of the various extraction technologies currently available, carbon dioxide (CO2) extraction stands out as one of the cleanest, safest and most efficient. CO2 extraction comes in two forms: supercritical and subcritical.

Both variants retain the plant's beneficial compounds without contamination by harmful substances. residual solvents, The result is a superior quality product with a more pleasant taste. In this article, we'll take a look at how CO2 extraction works and the key factors that distinguish it from other extraction techniques.

Why use carbon dioxide extraction?

Carbon dioxide is the most commonly used compound in high-pressure extraction. It has a number of advantages over other solvents used for botanical extraction.

Firstly, carbon dioxide is a non-toxic substance that is readily available commercially at a lower cost than other chemical solutions. In addition, carbon dioxide is environmentally safe, easy to use and produces a superior quality product, generally free of any by-products or residues. Temperature, time, flow rate and pressure can be manipulated to enable precise extraction of specific cannabis compounds.

This technology is commonplace in the botanical extraction and food industries.

How does CO2 extraction work?

Carbon dioxide extraction uses CO2 under pressure as a solvent to extract the desired compounds from cannabis. It requires specialized equipment, which can be costly. The actual process, however, is relatively straightforward. The carbon dioxide extraction method involves two basic steps.

First, crushed cannabis solids are placed in the extraction chamber. Pressurized carbon dioxide is pumped into the chamber, where it dissolves the plant material and separates compounds such as cannabinoids.

In a second step, a decompression valve facilitates the release of the material into a separate container, where heat and pressure encourage the cannabis compounds to separate from the carbon dioxide. The carbon dioxide is then exposed to a different temperature and pressure. It then stabilizes as a gas and returns to the CO2 tank, leaving behind a cannabis oil amber in color.

What's the difference between subcritical and supercritical CO2 extraction?

CO2 extraction comes in two forms: supercritical CO2 extraction and subcritical CO2 extraction. These are similar extraction methods, with two essential differences: temperature and pressure.

Supercritical CO2 extraction

CO2 reaches supercritical temperature at just above room temperature, which means it can be converted into a liquid, enabling the safe extraction of volatile active compounds that may be degraded by heat. Supercritical fluid extraction (SFE) uses CO2 in this state, where it exhibits both gaseous and liquid properties. In this supercritical phase, it moves through the plant material like a gas, but dissolves the active compounds. trichomes like a liquid.

The compound-rich solvent is then sent into a vessel that lowers the pressure and temperature, separating the cannabinoids and the compounds. terpenes. SFE captures larger molecules, such as waxes and lipids, resulting in a thicker substance that needs to be processed or "blended". winterized to remove these undesirable compounds. But because of its relatively low cost and wide availability, supercritical carbon dioxide (CO2) has been the preferred solvent for SFE products.

Subcritical CO2 extraction

Subcritical CO2 extraction involves a similar process, but at a lower temperature and under less pressure. The pressure causes the CO2 to liquefy, but no heat is used, meaning that more terpenes and other compounds are preserved. The subcritical extraction method takes longer than supercritical extraction and produces a lower yield. However, it produces a higher-quality product that preserves various elements of the cannabis plant, such as essential oils, terpenes and cannabinoids. Subcritical extraction yields a substance that does not contain fats, waxes or lipids, making it possible to obtain a high quality product. winterization less necessary.

Supercritical CO2 extraction is the most commonly used CO2 extraction technique for cannabis, as it offers higher yields more quickly. However, subcritical extraction is becoming increasingly popular as it is not as aggressive on the plant. Supercritical CO2 extraction can sometimes be too robust for certain terpenes, resulting in the loss of these compounds. Cannabis products that emphasize whole-plant benefits can benefit from subcritical CO2 extraction.

Is CO2 extraction safe?

When carried out by qualified professionals in properly equipped laboratories, CO2 extraction is one of the safest extraction techniques available. From an environmental and health point of view, it is less toxic than petroleum-derived hydrocarbons such as butane or propane.

CO2 has another feature that also contributes to its safety. Any residual CO2 remaining in the extract evaporates, so there is no residual solvent in the product.

Is CO2 extraction better than other methods?

The relative safety and non-toxicity of CO2 extraction generally make it a more attractive option than other extraction methods. The versatility of the technology also offers an advantage over other methods. By modifying temperature and pressure, different cannabinoids, terpenes and other compounds can be targeted, allowing the extraction process to be customized for different formulations. Most importantly, the very nature of the CO2 extraction process tends to result in a superior product.

That said, these advantages come at a price. CO2 extraction equipment is expensive, which can put it out of the financial reach of small cannabis businesses.

Is CO2 extraction better than butane extraction?

CO2 extraction is safer than butane because it's non-flammable, cleaner and guarantees no chemical residue. Butane offers a rapid extraction process, but it is a volatile solvent, and control over how cannabis compounds are extracted from the plant is limited.

In comparison, CO2 extraction is adjustable and enables various plant compounds to be separated in a segmented process.

Is CO2 extraction better than cold pressing?

Cold pressing is the extraction technique most commonly used for the hemp and the CBD. It is carried out at low temperatures, so there is no thermal degradation of the plant's various potentially beneficial compounds. Cold-pressing methods produce less total oil per batch than CO2 extraction, as CO2 requires some heat to break down the plant material more effectively.

Cannabis extracted at lower temperatures can offer its own advantages. According to a study, Unheated cannabis has a lower rate of undesirable pharmacological effects and may be associated with better tolerance. Cold-pressed oil may also contain more monoterpenes which are sometimes lost during the CO2 extraction process.

Can CO2 extraction be used to extract CBD?

Through the interplay of temperature and pressure, an extractor can «select» the cannabinoids it wishes to extract. CBD, for example, can be extracted using supercritical CO2. In France, some companies offer CBD extraction services, allowing French CBD to be grown locally.