What is CO2 Extraction? How Is It Used for CBD?

As topical and edible cannabis products gain in popularity, manufacturers are continually looking to improve their CBD extraction processes to yield high-quality products for consumers.

Various methods exist for cannabis extraction, from the simple olive oil extraction method at-home cannabis enthusiasts regularly use to hydrocarbon and chemical solvent extraction methods used in many processing plants.

However, the CO2 extraction method used for CBD, specifically supercritical CO2 extraction, seems to trump them all, yielding high-quality and pure cannabis products every time. Let’s explore why that is and look at the process in detail.

What Is CO2 Extraction?

Carbon dioxide (CO2) is a versatile solvent when heated and pressurized, making it ideal for extracting and isolating active compounds and oils from plants. In the cannabis industry, this safe, reliable extraction method isolates active compounds like cannabinoids and aromatic terpenes from hemp without destroying their potency.

Some manufacturers still use other popular extraction methods as well, namely:

• Olive oil extraction
• Solvent extraction
• Steam distillation

These extraction methods are not as good as CO2 extraction as they often destroy some active compounds reducing the effectiveness of the “Entourage Effect,” which is highly prized in the industry. Even so, understanding how these other extraction methods work will help you understand why supercritical CO2 extraction is the better approach.

Olive Oil Extraction

Olive oil extraction is relatively simple and the most common at-home CBD extraction method. The hemp is heated to 248°F (129°C) for 60 minutes or 284°F (140°C) for 30 minutes, then added to olive oil with a temperature of 212°F (100°C) for 2 hours to isolate the active cannabinoid compounds.

This method is safe and inexpensive, but the CBD yield is low, and the resulting CBD oil isn’t shelf-stable. It will need to be used relatively quickly and stored in a cool, dark place to be of any use.

Steam Distillation

This extraction method relies on steam to isolate cannabinoids. They are extracted as a vapor and then cooled and condensed, separating the pure CBD oil from the extract residue.

Steam distillation is simple, inexpensive, and doesn’t require chemical solvents, which are unsafe to use and often leave harmful residues. However, the CBD concentrations produced by steam distillation are not consistent, and the process can damage the much sought-after properties of some heat-sensitive active compounds in hemp.

Chemical Solvent Extraction

Solvent extraction uses food-grade ethanol and hydrocarbons like butane and hexane to extract cannabinoids and terpenes. Hemp leaves are added to the chemical solvent, and once enough CBD has been isolated, the extract is heated to yield pure CBD oil.

This extraction method is ideal for extracting CBD for edibles when using low-grade ethanol because the end product is safe for consumption. However, the process itself can be dangerous. When inhaled, butane can cause lung irritation. Chemical solvent extraction is also disadvantageous as it destroys beneficial plant waxes and oils and may produce and oil containing chlorophyll or other contaminants.

In-Depth: The Process of Supercritical CO2 Extraction

Now that we’ve examined a few other extraction methods, we can look at the CO2 extraction process in more detail. CO2 extraction utilizes heated and highly pressurized carbon dioxide gas to isolate pure active compounds collectively known as phytocompounds from raw hemp.

This highly tunable gas is the perfect solvent for extraction—so long as it’s at a specific temperature and pressure range. CO2 extraction results in a clean, high-quality product that’s safe and non-toxic.

Supercritical carbon dioxide is highly fluid carbon dioxide, existing at or slightly above the liquid-vapor critical point. At this maximum temperature and pressure, the gas exists in equilibrium as a fluid, filling space like a gas while exhibiting the density of a liquid. CO2’s liquid-vapor critical point occurs at a temperature and pressure of approximately 88°F (31.1°C) and 1,073 psi, respectively.

This prized extraction method is the cannabis industry’s gold standard for making premium CBD products yielding pure and clean oils and tinctures. The most notable advantages of supercritical CO2 extraction are that it:

• Is highly effective in removing essential compounds from the hemp plant without leaving any harmful or unwanted residues and plant matter behind
• Protects cannabinoids from decarboxylation and degradation
• Enables manufacturers to precisely separate out extracts of differing weights
• Is cleaner, safer, and greener than many solvent extraction methods

Supercritical CO2  vs. Subcritical CO2 Extraction

There is also another CO2 extraction method known as subcritical CO2 extraction. While this extraction process is similar to supercritical CO2 extraction, it occurs at lower temperatures and pressures, with the CO2 gas remaining liquid rather than a liquid gas. Subcritical CO2 extraction for CBD oil is not as popular as it is more expensive, time-consuming, and produces lower yields.

How Supercritical CO2 Extraction Works

Supercritical CO2 extraction relies on a precise process and follows these steps:

1. Gaseous CO2 is passed through a sealed chamber in the extractor, highly pressurized, and exposed to temperatures as low as -70°F (-57°C), converting it into a liquid.
2. The CO2 liquid is then re-pressurized and reheated to a supercritical fluid state, gaining the unique properties of both a liquid and a gas.
3. The supercritical CO2 flows through a chamber containing raw hemp.
4. The gas passes through hemp, dissolves the plant’s protective trichome membrane, and reaches the active plant compounds, isolating and extracting them.

Supercritical CO2 extraction yields a thick, full-spectrum CBD extract containing cannabinoids, essential oils, terpenes, plant waxes, omega-3 lipids, omega-6 lipids, and minute amounts of chlorophyll.

Winterization

Following extraction, the hemp extract undergoes a further process of purification known as winterization. This process uses food-grade ethanol at a temperature of -4°F (-20°C) to extract the CBD oil and separate the unwanted lipids, waxes, chlorophyll, and other plant matter. Proper winterization helps improve flavor and helps achieve a more favorable consistency in the end product.

Here’s how the winterization process works:

1. The hemp extract is mixed with ethanol to thin it out, making it easier to filter later in the process, and then frozen for approximately 24 hours.
2. The fats, waxes, and other plant materials solidify.
3. The chilled extract is then filtered, leaving the fats, waxes, and excess plant materials on the filter paper.

Some manufacturers will repeat the winterization process or parts of it (particularly filtration) several times to ensure absolute purity.

After winterization, the remaining ethanol needs to be removed. As ethanol has a lower boiling than hemp extract, it will evaporate first when heated. This process is usually done using a rotary evaporating machine, which also allows the alcohol to be recovered and reused in the future.

Why Supercritical CO2 Extraction Is the Best Way to Extract CBD

CO2-extracted CBD yields a full-spectrum CBD oil that gives consumers the “Entourage Effect.”

Perhaps the most famous benefit of CO2 extraction is its precision in extracting multiple cannabinoids and terpenes, yielding full-spectrum CBD oil. There are three types of CBD, essentially based on how “filtered” it is, that is, what has and hasn’t been removed:

• Isolate: Isolate is, as the name suggests, isolated CBD. There are no other cannabinoids present.
• Broad Spectrum: Broad-spectrum CBD is processed to remove THC (the psychoactive compound in cannabis). Keep in mind that hemp CBD never contains more than 0.3% THC. It won’t get you high. However, at very high regular doses, it could potentially result in a positive drug test.
• Full Spectrum: Full-spectrum CBD contains all the cannabinoids and terpenes left after extraction and winterization.

The cannabinoids and terpenes found in cannabis are beneficial to humans and animals. Research has shown that when these active compounds are combined into one product, the full range of benefits is amplified, offering more medicinal value than products containing CBD alone. This beneficial effect is commonly known as the “Entourage Effect.”

While premium CBD isolate is useful in certain circumstances, full-spectrum CBD products are more versatile and applicable to various products, including edibles, topicals, and tinctures. Take, for example, the cannabinoids cannabinol (CBN) and cannabigerol (CBG).

These active cannabis compounds have specific health benefits. CBN is an excellent sleep aid and works to relieve pain and inflammation, while CBG has been shown to regulate appetite and sleep and alleviate pain.

Full-spectrum CBD also contains more than 200 aromatic terpenes, such as β-Caryophyllene and β-myrcene. These terpenes have highly sought-after analgesic, antimicrobial and anti-inflammatory properties. They can also promote relaxation and sleep or boost energy levels.

CO2 extraction is precise.

Supercritical CO2 extraction is the highest-quality method CBD extraction. This method is precise but also economical, clean, and safe compared to other extraction methods. For instance, butane extraction can leave traces of heavy metals and cause lung irritation when consumed. However, supercritical CO2 extraction yields no residual solvents.

CO2 gas is also highly tunable, which means that manufacturers can set its solvation strength incrementally, making adjustments in the supercritical CO2 gas’s density. The versatility of CO2 gas allows for more targeted terpene and cannabinoid profiles.

Cannabis manufacturers also use CO2 extraction to produce safe edibles. Even though these edibles undergo further processing with food-grade ethanol, most of the CBD is extracted using supercritical CO2 extraction.

Supercritical CO2 extraction is safer.

This method of extracting CBD oil yields a purer, cleaner product and poses minimal health and safety risks. Vent lines used in the processing plants are small, and the chances of ignition or explosion, even given the use of flammable solvents, are minimal.

The only other safety equipment required is a CO2 monitor to detect possible leaks. Although the initial investment required to set up a CO2 extraction plant is higher than that of a steam distillation or ethanol plant, the investment is worth it.

CO2 extraction is economical.

CO2 is inexpensive, non-flammable, and chemically inactive, making it a better choice for CBD extraction than chemical solvents. It is also readily available from suppliers and is easy to transport as it is non-toxic.

Even better, CO2 gas is recyclable and can be repeatedly reused in the extraction process, which saves money. CO2 also yields high-content, pure, full-spectrum CBD as it breaks down the protective trichome membrane quickly, extracting higher levels of phytocompounds while leaving fewer residues than chemical solvents like hexane, propane, and butane.

CO2 extraction is eco-friendly.

Another of the most recognizable benefits of CO2 extraction is how environmentally friendly the process is. CBD products extracted using this method are healthier and easy on the environment as there are no harmful solvent residues left behind. Chemical solvents like butane and hexane are known lung irritants that could negatively affect the end user’s health.

Also note that while CO2 gas is a greenhouse gas and considered bad for the environment, CBD CO2 extraction does not increase greenhouse gas emissions.

Where to Buy CO2-Extracted CBD Products

For cannabis consumers, CO2-extracted CBD products are easily accessible online and in approved cannabis shops and cafes. Most reputable retailers like SUPA Naturals stock these cannabis products because they are potent and safe.

At SUPA Naturals, our full-spectrum CBD oils, THC-free edibles, and full-spectrum topicals use supercritical CO2-extracted CBD from high-quality US-grown hemp plants. They contain zero cutting agents, toxins, solvent residues, artificial fillers, and most importantly, they are free from heavy metals, pesticides, and microbes.

You can verify this point for every product we sell via third-party lab reports and Certificates of Analysis (COAs).

CO2 Extraction For CBD: Final Thoughts

CO2 extraction retains more terpenes and cannabinoids than any other extraction method, offering consumers CBD topicals, tinctures, and edibles that provide improved benefits and more of them.

While CO2-extracted CBD products may end up costing a little more than CBD products extracted using other methods, these products are purer, cleaner, and greener, which makes them a safer, eco-friendlier, and more sustainable option.

To enjoy some of the highest quality CO2-extracted CBD products online, be sure to explore the official SUPA Naturals store or try our CBD quiz to find the right products for your needs. We have some of the most effective, independently tested, premium CBD products on the market. We even offer CBD for pets!