Carbon dioxide, or CO2, exists all around us. It’s found in the bubbles in our soda, the exhaust from our cars, and even in our fire extinguishers. This colorless gas has many uses in modern industry.
These days, top of the line producers are using CO2 extraction to produce some of the highest-quality cannabis concentrates on the market. This method of extracting cannabis oil offers many benefits to manufacturers and consumers alike: it’s efficient, it’s sustainable, and it produces a clean and potent product.
Check out our guide to CO2 extraction to learn all about this process and find out why many consider it the best method available.
What is CO2 Extraction?
CO2 extraction refers to a process where supercritical CO2 is used in a closed-loop system to act as a natural solvent. It’s often used to extract essential oils or other compounds from organic matter. This technique is now increasingly preferred in the cannabis industry as the best method for extracting cannabinoids like THC and CBD.
CO2 extraction requires high pressure and precise temperature control, and is usually performed by experienced professionals in a controlled setting. Extractor units can cost anywhere from $8,000 for a small machine to hundreds of thousands of dollars for an industrial extractor with fractionation capabilities.
While some individuals have succeeded in creating their own closed-loop extraction systems, we recommend you leave this complex process to the professionals. If you want to try your hand at a more traditional extraction method at home, try making your own bubble hash.
What is Supercritical Carbon Dioxide?
Under normal conditions, carbon dioxide exists as gas in the atmosphere. Supercritical CO2 refers to carbon dioxide held at a specific pressure (above 1,070 psi) and temperature (above 31° C/87.8° F) to achieve the properties of both a liquid and a gas.
More specifically, supercritical carbon dioxide expands to fill a container like a gas while maintaining the density of a liquid. This state is ideal for maintaining the integrity of cannabinoids and other extracted organic material.
What is CO2 Extraction Used for?
CO2 extraction has recently gained more attention for its role in the cannabis industry as a method for making THC concentrates and CBD products, but supercritical fluid extraction has been around since it was developed by the Kerr-McGee corporation in 1979. CO2 extraction is used to create many other items commonly found on product shelves today, including:
- Tobacco extract for vapes and electronic cigarettes.
- Flavorings, such as vanilla extract or almond extract.
- Aromatherapy essential oils such as tea tree and lavender.
- Omega-3 supplements.
- Perfume and fragrance oils.
The CO2 Extraction Process
CO2 extraction takes place within a closed-loop system. Some of its major mechanical components include a CO2 tank, extraction chamber and a separator. The system is propelled by a pump. Let’s take a step by step look at the CO2 extraction process.
- To begin, the CO2 tank is filled, and the plant matter, or biomass, is loaded into the extractor chamber.
- Supercritical CO2 is pumped from the CO2 tank into the chamber. The CO2, acting as both a liquid and a gas, coats the plant material and works as a solvent to separate the raw lipid material (cannabis oil, waxes, and resins) from the rest of the plant matter.
- The mixture of supercritical CO2 and raw oil floats upwards past a pressure release valve and into a cyclonic separator. The lower pressure conditions in the separator allow the raw oil to sink into a collection vessel while the carbon dioxide rises and is routed back to the CO2 tank to be used again.
- Any residual CO2 within the final product dissipates as a gas when exposed to air.
From here, the raw product may be further refined to isolate various cannabinoids or terpenes through the process of fractionation. For example, THC distillate isolates only the THC within the cannabis extract while removing other cannabinoids and plant compounds.
Whether you’re purchasing CBD oil or live resin, the highest quality cannabis concentrates are lab-tested to ensure that your product is free of contaminants such as mold, heavy metals, and chemical residues.
Benefits of CO2 Extraction
There are so many reasons why supercritical CO2 extraction has become one of the preferred techniques for creating cannabis extracts. Carbon dioxide is abundant, and it’s considered a natural resource.
Of course, when excessive carbon dioxide is emitted into the atmosphere, it can cause a harmful imbalance to our environment, but it’s important to note the CO2 extraction has nothing to do with fossil fuels.
In fact, CO2 extraction is considered a far more sustainable method when compared to butane and hexane extraction techniques.
Cannabis concentrates that have been extracted using carbon dioxide contain no residual chemical solvents, and are thus considered a cleaner and generally safer cannabis product. Those who use cannabis for medicinal reasons or to promote wellness may particularly prefer to purchase products that employ this method.
CO2 Extraction vs. Butane Extraction
Another popular method for creating cannabis concentrates is butane extraction. The resulting product is known as butane hash oil, or BHO. Butane is found in cigarette lighters and is often used as a fuel source for grills, outdoor heaters, and more. The extraction process is similar, but butane hash oil comes with a few drawbacks.
Both butane extraction and CO2 extraction are best performed in a controlled, professional setting for best results, but butane carries with it certain health and safety risks that carbon dioxide does not.
One of the greatest risks is that butane is a hydrocarbon (a component of fossil fuel) that is highly flammable. There have been several reports of accidents and injury involving butane explosions in the process of making homemade BHO.
While CO2 extraction leaves behind no chemical solvents, the same cannot always be said for butane extraction. Butane hash oil that is produced by extractors in a professional setting are often more diligent in lab testing and removing residual butane than home extractors.
While butane is considered to have low toxicity, many cannabis users would prefer not to inhale residual chemicals at all.
Supercritical CO2 extraction is an innovative process that can produce some of the cleanest and most potent cannabis products on the market. Pick some of them up on your next trip to the dispensary and notice the difference that CO2 extraction makes!