How is CBD extracted from the hemp plant, and can you make your own CBD-infused oil at home? Read our CBD extraction guide to find out. CO2 extraction is by far the best method to produce full-spectrum CBD oils and leverage the entourage effect. How does it work and what are the benefits of using CO2 for extraction? Read on to find out! A cannabis concentrate made through CO2 extraction, which uses CO2 as a solvent to strip the cannabis plant of cannabinoids and terpenes into a concentrate. Learn more about CO2 oil from Leafly.
CBD Extraction: CO2, Steam Distillation, and More
We’d like to thank CBDfx and Natural Hemp Solutions for supplying us with images of the processes used in their labs.
Cannabidiol, or CBD for short, is an organic compound that is found in the cannabis plant, with the flowers of the hemp plant being the richest source. And in order for CBD to be added to a wide array of consumer products—think CBD oil, lotions, topicals, or CBD vape juice—the first step that manufacturers need to take is to extract it from the plant.
This guide will present the various CBD extraction methods, essentially explaining how full-spectrum CBD oil is obtained from the CBD strains of cannabis. Some of these methods have been used in various industries for decades or even centuries, far before CBD oil was even a thing. Examples include essential oil extraction, decaffeination (and caffeine extraction) of coffee beans, and even beer production. In all cases, the idea is the same: how to extract a valuable resource out of plant material.
If you are interested in the ins and outs of CBD extraction from cannabis strains high in CBD, here’s a breakdown of the most commonly used CBD methods.
Supercritical CO2 extraction
The word “supercritical” sounds real fancy, but it is actually a term that’s very commonly used in chemistry. Simply put, a substance in its supercritical state possesses characteristics of both a gas and a liquid.
When supercritical CO2 is used in CBD extraction, its gas properties allow it to effuse through all plant matter, while its liquid properties allow it to extract compounds efficiently. The exact process varies, and some labs start the extraction with liquid CO2 while others start with CO2 in gas form. In both cases, manufacturers add CO2 in a chamber that includes plant material and use the exact amounts of pressure and temperature needed for CO2 to reach its supercritical state. At this point, and with the help of some additional heat, CO2 acts as a solvent and causes the plant material to separate, carrying with it all the essential compounds. Once done, CO2 is separated from the organic compounds, and manufacturers are left with full-spectrum CBD oil.
While it requires qualified personnel and there are higher costs associated with the equipment needed for supercritical CO2 extraction, it is by far the most efficient and quickest method to extract CBD. It is also environmentally friendly due to the limited amount of emissions, and safer than extractions that use certain solvents as CO2 is “generally regarded as safe” by the FDA.
- The most efficient method
- CO2 is regarded as generally safe
- Quick (once everything is in place)
- Environmentally safe
- Expensive (equipment costs)
- Needs qualified personnel
Steam distillation is a centuries-old process that’s commonly used to distill alcohol as well as extract essential oils from organics. The process is much less complicated than CO2 CBD extraction. First, plant matter is introduced in a distillation tank. With the use of water and heat, the produced steam carries oils to the top of the tank, and it is then passed through a condenser, resulting in a mix of water and oil. The mix then goes through further distillation to separate water and oil, and the result is full-spectrum CBD oil.
While this CBD extraction process is much simpler, there are some downfalls. It is more prone to error, much less efficient, and may potentially damage part of the essential oil profile of the plant. Due to these reasons, steam distillation is very rarely used to extract CBD nowadays, but many labs still use some type of distillation in the process of isolating CBD from full-spectrum oil.
- Relatively easy to perform
- Low cost
- Not very efficient
- Not consistent
- Resulting CBD oil is less potent
This method is also centuries old and is somewhat of a middle point between CO2 extraction and steam distillation when it comes to complexity and efficiency. It bears many similarities to CO2 extraction, albeit without the advanced methodology that’s behind the “supercritical” part.
In layman’s terms, this type of extraction involves mixing plant material with some type of solvent that will carry the essential oils given the right conditions and enough time. Some of the most popular natural solvents are alcohol (ethanol) and natural plant oils (including olive oil), with alcohol being much more efficient in dissolving the plant’s compounds. But due to the higher cost associated with ethanol, many manufacturers choose to go with synthetic solvents (hydrocarbons like butane or hexane), which may end up in lower quality, or even CBD oil that’s unfit for consumption if they’re not removed properly from the final product.
Solvent extraction is a delicate CBD extraction process and its pros and cons, as well as the consistency of the resulting oil, varies greatly depending on the solvent used. It can be more efficient than steam distillation if performed properly, but it carries a lot of risk and most labs choose CO2 extraction if they can afford it.
- More efficient than steam distillation
- Can be performed with natural oils
- Relatively safe if natural oils are used
- Varied results in final product
- Not as efficient as CO2 extraction
- Synthetic solvents are dangerous to handle
- Synthetic solvents need to be completely removed from final product
How to extract CBD at home
At this point, you may be wondering if there’s any way you can extract CBD at the comfort of your own home. The short answer is “yes”, but it really depends on how willing you are to do further research. The following is not going to be a real step-by-step guide, but it can serve as a starting point and give you some basic guidelines.
Olive oil extraction
Possibly the simplest way to extract CBD oil, as it only requires some CBD-rich bud, olive oil, and some basic kitchen equipment to ensure a steady supply of heat. If you’ve ever made cannabutter, then technically you have already utilized this method before. The only difference in this case, is that you are using hemp and olive oil—but olive oil can easily be swapped out for the oil or butter of your choice. This includes regular butter, coconut oil, hempseed oil, etc.
The first step for olive oil extraction is decarboxylation, i.e. activation of the compounds of plant material with the use of heat (there’s more info in the following section). Trimmed hemp flower in an oven tray heated between 240 and 280°F (115-135°C) for up to an hour should do the trick. Once this step is taken care of, the resulting activated cannabis is mixed with olive oil and heated at low temperature (ideally in a double boiler) for around two hours. The only thing left to do at this point is to use a filter to strain the mixture and separate the oil from the plant material. The result: CBD-infused olive oil.
While this is the easiest and least risky way to extract CBD oil, it is certainly not the most efficient. As with most DIY projects, there’s always room for user error. But even if you do everything right, you are going to sacrifice a large part of the organic compounds of the plant and you will produce less potent oil than a lab would. For these reasons, extracting CBD at home is an interesting experiment, but if you want to reap all the benefits of CBD it is advisable to get it from a reputable source instead.
Activation and purification
While technically not steps of CBD extraction, activation of active organic compounds and purification of CBD oil are two processes that are very important in CBD production. The most common methods used for these purposes are decarboxylation and winterization.
The active organic compounds of the cannabis plant come in their acidic forms. In order to go from THCA and CBDA to THC and CBD, manufacturers need to apply heat and decarboxylate the compounds—that’s the lab equivalent to lighting up a joint. Heat removes a carbon molecule from the organic compounds and turns them into their active counterparts.
Decarboxylation may take place before or after the extraction, and the exact methodology followed is highly dependent on this choice. But it is an essential part of the CBD oil production process, as non-activated compounds have little to no effect on the user.
While not as essential as carboxylation, winterization is a very common process that ensures that the final product of the extraction is as pure as possible. Simply put, the process of winterization employs solvents (usually ethanol) and low temperatures to ensure that lipids and other impurities are removed from an oil extract. This takes place as one of the final steps before full spectrum oil is obtained.
Winterization is not always performed, but it is a very important process when the final product is intended to be vaped. Some terpenes and other compounds are also filtered out during this process, but many manufacturers choose to add terpenes to their CBD oil after winterization.
CBD extraction: the takeaway
These are the most commonly used CBD extraction methods and, as expected, each comes with its own advantages and disadvantages. The main takeaway from this guide should be that the reason you may have seen “supercritical CO2 extraction” in ads and promotions is not just that it sounds cool (although it does!) Simply put, CO2 extraction is by far the cleanest and most efficient CBD extraction method—and a no-brainer for any lab that can actually afford it.
This doesn’t mean that all CO2-extracted CBD products are better by definition. But if a lab invests in the equipment that’s required for the most technically demanding extraction method, chances are that they know what they are doing. When in doubt, check lab tests, and always choose third-party tested CBD products from reputable sources.
How to Extract CBD Oil from Hemp & Cannabis Using CO2 Extraction
The CBD industry has coined a reputation of the Wild West due to the lack of regulation around the labeling and manufacturing standards. Research is one of the paramount considerations one should take when looking for CBD oils.
The source of hemp is very important, but the extraction method can make or break the quality of the end product.
Fly-by-night companies cut costs by utilizing chemicals such as butane and hexane. Aside from lying to customers and destroying volatile terpenes, chemical solvent extraction may leave a toxic residue if not purged properly.
Let’s make it clear, we don’t want to ingest toxic chemicals in a product that is supposed to be healthy.
That’s why you should purchase from brands that use CO2 extraction technology. This method ensures that the end product contains more terpenes and cannabinoids because it doesn’t use additional heat or solvents.
There is a reason why CO2 extraction is becoming popular. A study by Jin et al., published in the journal Natural Product Communications, examined the effects of supercritical CO2 extraction on a type of Japanese Cypress. The researchers were able to determine the essential oil makeup of the trunks and leaves of the tree.
Let’s take a closer look at CO2 extraction and its benefits for CBD users.
What is CBD CO2 Extraction
CO2 extraction involves the use of pressurized carbon dioxide to pull as many desirable compounds from the cannabis plant as possible — including cannabinoids, terpenes, and the plant’s essential waxes. What you get is a healthy-looking, gold, and viscous extract that you can later suspend in a carrier oil or use with thinners to make it vapable.
For CO2 extraction, versatility is the name of the game. When put under a specific temperature and pressure range, it can act as a solvent, but without the dangers associated with toxic solvents like butane or hexane. In its supercritical state, CO2 yields premium-quality extracts with consistent potency levels and exceptionally high purity.
A funny thing is that CO2 extraction isn’t reserved exclusively for CBD oils. In fact, this is a standard method in the herbal and food industries. If you have decaf coffee in your kitchen, then you have a product that relies on CO2 extraction to pull caffeine from coffee beans. Also, the majority of essential oil production relies on this technology.
Forward-thinking companies realized that traditional extraction methods carried certain risks, such as flammability, solvent toxicity, and wastefulness. Before supercritical CO2 was introduced, brands had relied on solvents such as methylene chloride, trichloroethane, or ethyl acetate — all of which are far from safe.
What Does “Supercritical CO2 Extraction” Mean?
There are a few ways to make CBD oils using CO2 extraction, but supercritical CO2 extraction is widely believed to be the industry’s golden standard. This technology relies on a process known as supercritical fluid extraction. The process involves using supercritical fluids to pull one component from another. CO2 is the most commonly used ingredient in this process, although some manufacturers modify it with a co-solvent such as alcohol.
At standard pressure and temperature, CO2 acts like a gas. When it comes to supercritical CO2, it remains in the fluid state of the gas, which can only happen when the producer applies pressure and temperature that are above their critical levels.
Here’s how supercritical CO2 extraction works in a nutshell:
- The extractor uses the CO2 gas and runs it through a chamber. At this point, the temperature is kept as low as -70 degrees Fahrenheit but the pressure is being gradually increased.
- The gas turns into a fluid.
- In this state, CO2 possesses both gas and liquid properties. In other words, it fills space like a gas, while maintaining the density of a liquid.
- The supercritical CO2 passes through a chamber that is filled with the raw cannabis material.
- The fluid passes through the plant material, dissolving the trichomes’ membranes. This allows the CO2 to capture a significant amount of the active compounds.
The critical temperature of CO2 has been recorded at 89.78 degrees Fahrenheit and the pressure is 73.8 bars, which translates to 7.38 million Pascals, or 1,070 pounds per square inch. This is the data from the February 2010 edition of Chemical Engineering.
In a 2014 study published by Peach and Eastoe in the Beilstein Journal of Organic Chemistry, the authors described supercritical CO2 as “a solvent like no other.” The study focused on how supercritical CO2 could contribute to the development of green chemistry.
What is Subcritical CO2 Extraction?
While subcritical CO2 extraction isn’t as common as the supercritical one, it has its place in the CBD industry. The reason why only a few manufacturers use this variation is a smaller yield and time consumption.
Basically speaking, subcritical CO2 extraction is a similar process to supercritical, but it operates on lower temperatures and lower pressure.
Although it takes more time and is less efficient, it retains more cannabinoids, terpenes, and essential oils, reflecting the original phytochemical profile of cannabis.
Unlike subcritical CO2 extraction, the supercritical method produces a thicker oil that has a consistency similar to peanut butter. That’s because the higher temperatures and pressure can extract larger compounds, such as chlorophyll, waxes, and omega-3 and 6 fatty acids. Then, the product goes through the winterization process, which removes these substances, leaving behind the filtered CBD oil.
Subcritical CO2, on the other hand, yields extracts that look and feel like molasses.
Benefits of CO2 Extraction
The major benefit of using a CO2-extracted cannabis extract is the lack of additional solvents or too high temperatures. CO2 is considered a ‘green solvent.’ The use of carbon dioxide yields cleaner and healthier products. CO2 is a natural ingredient that appears as part of the breathing process upon exhaling.
Unlike solvents such as butane, supercritical CO2 doesn’t leave behind any toxic chemical residues. It is also recyclable, which makes it cost-effective.
The benefits of CO2 extraction include:
- It is inert, non-flammable, and non-toxic.
- CO2 has moderate critical points
- The solvation potency can be fine-tuned by adjusting the compound’s density.
- It yields large quantities of pure extracts.
- CO2 enters its supercritical state in near-ambient temperatures, so it’s a perfect solvent for extracting volatile compounds.
CO2 Extraction and CBD Entourage Effect
Aside from providing a clean product, the biggest advantage of using CO2 extraction is its ability to extract larger quantities of cannabinoids and terpenes than other methods. The cannabis plant contains over 115 identified cannabinoids on top of hundreds of terpenes and flavonoids. Even though CBD and THC share many similar benefits, an increasing number of researchers now believe that the real magic happens when you can get all the naturally occurring compounds together in one product.
Although not as abundant as CBD and THC, cannabinoids such as cannabigerol (CBG) and cannabinol (CBN) have potential health benefits as well. For instance, CBN has a link with a significant decrease in physical discomfort levels, while CBG has neuroprotective effects.
Then there are terpenes, which also modulate the effects of cannabinoids. For example, limonene can increase the absorption of cannabinoids and enhance other terpenes, while alpha-pinene could counteract short-term memory problems associated with THC. Myrcene may reduce resistance in the blood-brain barrier, resulting in a more effective passage of beneficial chemicals in the body.
The above effects are described as the entourage effect. This phenomenon refers to the synergy between all cannabinoids, terpenes, and other cannabis compounds; the synergistic effects amplify the benefits of the CBD extract while modulating potential side effects. While high-quality CBD isolate has its applications, full-spectrum products are potentially a better option if the user is looking to maximize the efficacy of their CBD oil.
CO2 Extraction Equipment: Why Are Some CBD Oils More Expensive Than Others?
We’re not going to deny that supercritical CO2 extraction is expensive, which carries over to the final price of CBD oils that are extracted with this method. Companies invest heavy financial resources in equipment and the team of qualified scientists who will operate the machines. Only then can we talk about high-quality products.
An average cost of a CO2 extraction machine is around $450,000 — and there are certainly more expensive units out there. Within this price range, you can buy a machine that will process up to 200 pounds of dried plant material each day. That’s why it’s possible to produce premium CBD extracts on a broad scale. The CO2 extraction system has the biggest workloads in the industry.
The features of CO2 extraction machines include:
- High capacity
- Full automation
- The ability to mix supercritical and subcritical extractions
- A built-in CO2 storage tank.
Of course, you can find some budget-friendly powerhouses — around $175,000 — but they will be able to process less material than those from the top shelf. Such models usually process up to 107 pounds of biomass each day, which is still enough to run massive operations.
Small-scale businesses that want to employ CO2 extraction in their production practices can purchase extractors for “as little as” $4,000, although they look like dollhouses compared to the large-scale machines.
Nevertheless, one shouldn’t expect CO2-extracted CBD oils to be “cheap,” as this is a wrong oxymoron.
A Final Word on CO2 Extraction
When buying full-spectrum CBD oil, it’s wise to invest more money in a high-quality product that will not only be potent but also pure and safe for consumption. Most reputable manufacturers use supercritical CO2 extraction to make CBD extracts. Pressurized carbon dioxide yields clean and healthy products due to the lack of toxic solvent residue.
Another major benefit of CO2 extraction is the ability of CO2 to pull as many desired compounds from the plant as possible. This makes CO2-extracted CBD oil a more ‘complete’ product,’ as it squeezes the most out of the original phytochemical content of cannabis. A growing number of researchers and experts recommend such products and believe they provide better and more consistent results than isolates.
While CO2 extraction makes CBD oils more expensive than other methods, keep in mind that the investment is on both sides. The manufacturer invests a lot of money in high-tech equipment and knowledgeable staff, so the price is actually the reflection of that investment. No company will be charitable enough to sell their products at a loss.
A cannabis concentrate made through CO2 extraction, which uses CO2 as a solvent to strip the cannabis plant of cannabinoids and terpenes into a concentrate. CO2 oil can be high in THC, CBD, or another cannabinoid or specific terpene, and be of varying consistencies—the “CO2” in its name merely defines the process used to make it.
What is CO2 oil?
CO2 oil is a term used to describe any cannabis concentrate created by CO2 extraction. CO2 extraction relies on a closed-loop system and the chemical is purged from the final product.
CO2 oils can be of varying consistencies, such as shatter, crumble, honey, oil, etc. They can also be high in THC, CBD, or another cannabinoids or specific terpene.
How to use CO2 oil
CO2 oil is vaporized. It can come in vape cartridges and consumed through a vape pen, or as a concentrate, or dab, in the form of a shatter or wax. If in one of these forms, CO2 oil needs to be flash vaporized and consumed through a dab rig.