In terms of efficiency and safety in cannabis extraction, supercritical carbon dioxide (CO2) extraction stands out as one of the best methods for separating cannabinoids and terpenes from the cannabis plant material. While ethanol and hydrocarbon technology exists, this eco-friendly and safer solvent can be used for cannabis processing at any scale.
In terms of infrastructure costs, CO2 extraction is known for its high price of entry, even for tabletop units for small-batch producers. Despite its relatively high initial upfront, CO2 cannabis extraction is here to stay and may even earn a bigger role in the industry over the coming years.
Our extraction equipment guide covers the pros and cons of this extraction method and the best systems on the market. These systems can transform cannabis biomass into a high quality extract.
What Is Supercritical Carbon Dioxide?
Carbon dioxide is a gas formed during respiration and produced as a byproduct by a variety of industries. At a standard temperature and pressure, it can be found in the atmosphere as a colorless, odorless, and non-flammable gas. It is known as dry ice in its solid state.
Carbon dioxide turns into a liquid at pressures above 73psi. Its critical point is 1060psi and 87.8º F. If the temperature and pressure goes beyond the critical point, carbon dioxide will turn into a supercritical fluid, with properties of a liquid and a gas.
In this supercritical state, the carbon dioxide fills a container like a gas and has the density of a liquid. These properties help it completely soak cannabis material and strip the plant’s active ingredients without leaving any residual solvent in the final product.
For cannabis extraction, CO2 is a widely available solvent, and thereby, very affordable. In addition, this supercritical fluid can be recaptured and recycled within the closed-loop systems used in the industry, making it an eco-friendly option for production.
For cannabis processors, CO2 has a high rate of efficiency in extracting the plant’s valuable and therapeutic compounds. Operators can adjust temperature, pressure, and flow rate in their systems to pull out their desired compounds.
CO2 can pull out a wide range of cannabis compounds including cannabinoids and terpenes to create a concentrate product featuring the strain’s complete chemical profile.
Some of the benefits of CO2 include:
What Is Supercritical and Subcritical CO2 Extraction?
CO2 botanical extraction is commonly used in a variety of industries including the processing of hops for the beer industry. In fact, hops are part of the cannabis family and share many terpenes, the plant’s aromatic compounds. In the cannabis industry, this extraction method has proven itself worthy of its high cost of entry.
Supercritical CO2 extraction occurs at pressures above the gas’s critical point. Extractors use this supercritical fluid to fill a vessel full of cannabis biomass. CO2 has incredible solvent characteristics that can extract a high concentration of cannabinoids and terpenes from the biomass.
However, the high pressures and temperatures used in this extraction technique can end up degrading terpenes and other temperature-sensitive compounds. CO2 is known as a tuneable solvent enabling operators to manipulate the temperature and pressure to preserve the terpenes while efficiently extracting the heavier cannabinoid compounds.
Subcritical CO2 extraction happens at temperatures and pressures below CO2’s critical point. As a liquid, the CO2’s solvent efficiency lowers, but allows extraction technicians to carefully select the compounds like terpenes they want from the biomass.
While it takes much longer to complete runs, this technique is perfect for the extraction of terpenes, particularly because it uses lower temperatures.
CO2-Based Cannabis Products
CO2, in its supercritical state, can separate a wide range of cannabinoids and terpenes to create a variety of infused products. CO2 is prized for its ability to reap a wide spectrum of compounds to create full-spectrum products. For producers that want to reproduce the same aroma, flavor, and potency of a cannabis strain, this method is a great option.
Common CO2-extracted cannabis products include:
Supercritical CO2 Extraction Process
CO2 is one of the most popular solvents methods to extract cannabinoids and terpenes from cannabis, and its hemp variety. This process uses pressurized carbon dioxide as a solvent to remove cannabinoids and terpenes in a closed-loop system.
This method has many benefits including the ability to produce clean and pure concentrates. It is known for its safety as a solvent since it is non-flammable and has a significantly lower risk of leaving residual solvents in the end product. In fact, it is commonly used in the decaffeination of coffee and the extraction of essential oils from plants.
Compared to ethanol or butane and propane hydrocarbons, CO2 does not leave behind any residual solvents. For processors, this lack of residual chemicals in the end product is very important since many consumers use these products for medicinal and wellness purposes. Medical users may turn to CO2 extracts primarily for their relative safety and purity.
More importantly, CO2 is known as an efficient solvent in extracting the plant’s temperature-sensitive terpenes. It can create a full-spectrum product that contains the plant's original flavor and aromatic profile.
CO2 is known as a tunable solvent. During the extraction process, operators can manipulate the temperature and pressure to turn carbon dioxide into its supercritical state. It is able to extract cannabinoids and terpenes under high pressure and low temperatures.
When in the supercritical state, the solvent can pass through the biomass and release the oils contained inside. Many processors may perform multiple runs to remove different compounds at different temperatures and pressures.
Seasoned operators may do an initial run where they remove the terpenes first under a subcritical extraction environment. In the subcritical environment, operators use low pressure and low temperatures to retain the most fragile compounds from the plant.
Then, the operators do a supercritical run with high pressures and high temperatures to remove as many of the cannabinoids as possible.
CO2 may pull out undesirable plant material, which may require additional post-processing to remove the fats, lipids, and waxes from the extract. After the extraction process, the cannabinoid crude extract is separated and collected while the CO2 is condensed and converted back into a liquid, ready for use again.
Supercritical CO2 Extraction Equipment
This extraction method is performed with a closed-loop extractor that contains the solvent in a sealed environment and can recycle it for later runs. A closed-loop system does not release the solvent to the outside air.
Generally, carbon dioxide machinery has a few main parts to the system:
- One vessel contains the pressurized liquid carbon dioxide
- Another vessel contains the cannabis or hemp biomass
- A third vessel will separate the crude extract from the solvent
The type of equipment needed depends on the scale of the operation, the budget of the business, the size of the facility, and the type of products being produced. Many extractors start off with a small-scale unit and build out a facility naturally as they scale.
A variety of entry-level units are available for startups and even home extractors. Mid-range options and even high output systems can process hundreds of pounds per day or more.
A new breed of extraction systems are able to combine solvents to improve the efficiency and potency of the final product.
One type of system can use both CO2 and ethanol to reduce the processing time of the product, which is a major issue with CO2 equipment. An introduction of an ethanol solvent can help optimize the workflow and produce a better product.
When choosing between different CO2 systems there are few things to consider. Ideally, processors should consider these main variables: maximum pressure rating, high-wattage heaters, and the ability to change the temperature of the solvent.
These considerations are critical because the process requires high pressures, the necessity to deliver heat in an efficient way, and the ability to know the temperature of the solvent to fine-tune its density, depending on the desired end product.
Extractors are recommended to invest in a pump/flow monitoring system that gauges the amount of solvent being flowed to the extraction vessel. These pumps should be able to offer high flow rates.
Extractors must also invest in separation vessels with high maximum pressure ratings to give operators the ability to apply a variety of pressures to separate different components and create different cannabinoid-derived products.
One of the downsides of CO2 equipment is that a number of waxes and fatty acids can be separated with the solvent. Winterization is an additional post-processing method that uses ethanol and low temperatures to separate the waxes from the cannabinoids in a solvent. This part of the process can create a bottleneck in the workflow, especially if the system capacity does not coincide with the extractors throughput rate.
Extractors must also consider the solvent recovery following the winterization process. Solvent recovery systems must match the winterizing and filtering production throughput. Generally, rotary evaporation systems are used to recover the solvent.
After the initial extraction process, some operators choose to perform color remediation with filtration media such as natural zeolite to improve the purity and clarity of the crude extract. Chlorophyll in the extract can result in a dark oil with a bitter taste. Color remediation can create a lighter-color oil with minimal cannabinoid loss.
Color remediation can remove most of the chlorophyll and pigments from the crude extract. An additional color remediation column can be added to the system. It is a much more affordable color remediation technique that investing in short path distillation or flash chromatography to remove the chlorophyll in the extract.
Best CO2 Extraction Equipment
When it comes to cannabis extraction machines, there are plenty of options to choose from for everyone from home extractors to commercial producers who need to process thousands of pounds.
Isolate Extraction Systems
Isolate Extraction Systems carry botanical extractor machines for commercial and industrial purposes.
The smallest commercial units are designed to handle 5 liters with a flow rate of 8.2 kg per minute. On the larger side of the commercial line, commercial systems can handle 20 liters with the flow rate of 4.2 kg per minute.
Their industrial-capacity botanical extraction machines are capable of handling 50 liters with a flow rate of 8.2 kg per minute. Some IES systems can accommodate 200 liters with a flow rate of 42.2 kg per minute.
Apeks Supercritical carries a wide range of CO2 extraction systems for small-scale, mid-range, and high-output operations.
The introductory series, the fully-automated Bambino, has the same efficiency of the larger units but on a smaller scale. It is equipped with the energy-efficient Diaphragm Compressor Technology enabling cool processing and delivering 20 to 50% faster extractions with less energy use. 95% CO2 gas recovery reduces daily operational costs. It can process between 10 to 14 pounds of dried biomass in a 24-hour period. It is the perfect unit for startups.
For a slightly higher investment, the Transformer offers mid-range capacity and is designed for subcritical and supercritical CO2 extractions. It can process between 25 and 31 pounds of dry biomass in a 24-hour period.
Eden Labs offers entry-level and industrial-grade CO2 systems. The Hi-Flo unit (5 liter; 2,000 psi) is the entry-level model of commercial extraction equipment. Adjust temperature and pressure settings from a centralized console panel. This unit has a 95% CO2 recapture rate due to its closed-loop design.
The Hi-Flo FX2 can process over 100 pounds of biomass per day. All of Eden Labs’ products are made in accordance with the good manufacturing practice standards of the US Food and Drug Administration.
ExtractLAB’s supercritical CO2 extractors such as the most popular e-140 model can process an astounding 422 pounds per day and it only takes up 24 square feet of space.
The e-110 model is designed for smaller producers or research labs that need a small footprint. It can process between 1 and 1.5 kg per cycle in about 60 minutes or up to 79 pounds per day. In terms of oil recovery, it has a 90+% hemp efficiency and 95+% cannabis efficiency, all with a 24 square foot footprint.
For those just getting started in small batch production, the OCO Labs SuperC supercritical extraction system provides producers with an expandable solution in the form of a tabletop system.
At just 37 lb, the Super C has a 1 oz capacity and a run time of between 60 and 90 minutes for most extraction applications.
Independent temperature controls allow processors to dial the temperature to create their desired final products. For those that need more capacity, the expansion rack has a 4 oz capacity and a run time of 6 to 8 hours (minimum). This modular system allows you to upgrade your capacity without replacing the whole system.
Supercritical Fluid Technologies
Supercritical Fluid Technologies’ SFT-SP1100 provides processors with an affordable but powerful extraction system. It is designed primarily for companies who are just getting started in the extraction segment.
The compact footprint is a 1 liter processing vessel that delivers flow rates up to 176 grams per minute of liquid CO2. The vessel can complete a run in about 30 minutes and then the next 30 minutes the vessel is emptied and refilled for the next extraction. The result is 1.5 pounds of biomass extracted per hour.
Cool Clean Technologies
Cool Clean Technologies, a global leader in CO2 based production, has over 20 years of experience. The BX-450 system features a 450 liter system for industrial use that can process up to 500 pounds of dry material per day. Level up with the BX-610, a 600 liter system that can process up to 700 pounds of material per day.
Cedar Stone Industry
Cedar Stone Industry has a line of extractors capable of handling small- and large-scale volumes of cannabis. For instance, the Siphon-5 is a 5 liter extraction vessel. Cedar Stone Industry has vessels in 10, 50, and 100 liter capacities.
CO2 Extraction Equipment Financing
CO2 extractors are one of the most efficient ways to create infused products but high-quality equipment can be one of the most costly machinery in terms of investment in facilities. Supercritical CO2 extraction equipment can start as low as $30,000 for an entry-level system, which are usually not modular or expandable.
Many processors go all in with scaling in mind and invest in the mid-range or high range machines, which can cost between $75,000 and $125,000 or more. In order to stand apart from the competition, a higher investment in machinery will be required.
Getting financing for the CO2 extraction equipment is not possible through traditional banks since they are not lending to cannabis companies.
Many machinery manufacturers may offer high rates of financing with about a 25% default rate. Higher rates are offered to new entrants to the segment while lower rates from lenders are given to seasoned entrepreneurs who present a lower risk for them.
Generally, rates range from 10 to 20% per year adding at least $10,000 per year for a $100,000 piece of equipment. However, this equipment can commonly deliver $30,000 or more of monthly profit with a single unit, so it may be worth it in the long run to invest in this machinery.
Supercritical CO2 Extraction for Full-Spectrum Products
Closed-loop cannabis extraction equipment for CO2 extractors run the gamut from tabletop versions to ones that are built for large facilities. No matter what equipment is chosen, the result will be a pure and potent cannabinoid extract featuring a full spectrum of bioactive compounds.