Home / Blog / What is CO2 Extraction for CBD Oil? [Understanding the Basics…]
What is CO2 Extraction for CBD Oil? [Understanding the Basics…]

What is CO2 Extraction for CBD Oil? [Understanding the Basics…]

CBD oil, one half of the famous combo of THC and CBD that exists within cannabis, is becoming widely used as a natural therapy throughout the western world.

Due to its interactions with the endocannabinoid system, CBD has gradually become accepted as an way to treat a multitude of ailments, including arthritis, anxiety and even Parkinson’s Disease.

You can now purchase CBD oil at a variety of retailers, not even requiring a medical prescription. However, the actual mechanics of what CBD oil is remains a mystery for many people. Most know it simply as the oily substance you buy in a small jar, accompanied by a dropper and instructions of how to take it. But… what exactly is CBD oil, and how is it made?

If you’re going to put something in your body, it makes sense to understand how it’s made, so let’s take a look at the most common method used in CBD oil production – CO2 extraction.

Firstly though, what is CBD oil?

First Things First: What is CBD Oil?

CBD oil is made by suspending cannabidiol, a common substance within marijuana, in an oil. This substance usually exists in a ratio of about 10 parts THC to 1 part CBD within the plant.

CBD works to both compliment THC as well as to counteract some of its side effects within the body. In fact, some studies have shown that CBD is the main way to stave off the development of psychosis when imbibing a lot of marijuana.

When CBD enters your body, it interacts with the endocannabinoid system, which is responsible for a number of important bodily functions including the regulation of cellular regrowth, as well as a variety of brain functions like serotonin release. CBD triggers the CB1 and CB2 receptors within the endocannabinoid system, encouraging them to help your body heal and repair itself.

Considering the usefulness of CBD, it makes sense that people would want a way to imbibe this substance without having to go through the hassle of smoking full marijuana – sometimes people just want the healing, helpful properties of CBD without the psychoactive effects that accompany THC.

To aid this, manufacturers can distill the CBD out of the cannabis plant, allowing you to consume pure CBD without any of the other compounds. Once distilled out of the raw plant material, CBD is then suspended in inert oil – commonly hemp or coconut oil – so as to keep the CBD fresh and allow for easy application and administration.

The most common method of getting the CBD out of the cannabis plant and into the oil is a process known as CO2 Extraction. What is this process?

CO2 Extraction for CBD Oil – What is it?

Whenever the word “extraction” is used, it tends to sound like it has some sort of advanced, highly scientific application, perhaps even in a dangerous way.

Well, with CBD, the CO2 extraction process is actually pretty simple. However, it is generally divided into two separate methods – supercritical and subcritical.

Supercritical CO2 Extraction for CBD Oil

CO2, the compound of carbon and oxygen atoms that we exhale with every breath we take, has a few interesting properties at different temperatures and pressures.

If you take CO2, which is of course normally a gas, and heat it to above 31.10 degrees Celsius while at the same time exerting pressure equal to 10071 psi, CO2 becomes a supercritical fluid. This means that the CO2 has both the properties of a gas and a liquid.

With this, it is both able to effuse through solids like a gas, as well as dissolve materials and substances like a liquid. The reason this happens is because the CO2 has been heated and pressurized beyond its critical point, the point at which the lines between being a liquid or being a gas are rather… blurred.

Science can get a bit weird, can’t it?

Because the CO2 is neither a liquid nor a gas, but has the properties of both, it is able to be used quite usefully as a solvent. This means that the CO2 can be used to retrieve certain substances from others, depending on the temperatures you heat it to. This allows manufacturers to remove pure CBD from the cannabis plants while avoiding having to retrieve any other substances such as THC or chlorophyll.

The actual process and equipment used in CO2 extraction for CBD is actually very interesting, as it is an entirely closed system, as well being totally recyclable.

Supercritical CO2 Extraction for CBD: Process & Equipment

A key part of the supercritical CO2 extraction process is that the CBD is kept in a closed loop system, meaning it is entirely independent of other systems. The cannabis is kept in an extractor chamber, which is flooded with CO2 supercritical fluid, dissolving the cannabinoid and carrying it into a separate chamber.

From there, the CBD is diffused from the CO2, allowing the CO2 to reenter the system and be used again in the very same extraction process.

The remaining raw cannabis plant material is typically thrown away, or it can again be diffused in a separate system in order to extract THC or any number of desirable compounds.

However, the key issue with supercritical CO2 extraction is that it is exorbitantly expensive. The equipment required for the extraction can cost tens of thousands of dollars, sometimes even into the hundreds of thousands if buying on a commercial scale.

This renders the process, while desirable from a consumer standpoint, prohibitively expensive for the casual user.

Supercritical CO2 extraction has been demonstrated to be incredibly effective at retrieving the CBD oil; a study published by Laura Rovetto and Niccolo Aieta in the Journal of Supercritical Fluids found that the extraction efficiency was in excess of 92%.

However, supercritical extraction carries with it a series of disadvantages in that it will carry with it all the waxy, fatty compounds from the plant along with CBD. To combat this, another step has to be added in order to get truly pure CBD oil.

The Importance of Winterization

By superheating the CO2, it is possible to diffuse the CBD oil and carry it away from the plant, but it also has the ability to take with it some of the lipids and other fats that exist on the cannabis plant.

These lipids can prove dangerous to a consumer of the CBD oil, as well as imparting an uncomfortable taste and texture.

To combat this, manufacturers employ a process called winterization, which involves soaking the finished crude CBD oil in an alcohol solution, then freezing it for 24 hours.

In a similar method to how brandy is made through freezing distillation, the CBD will separate out from the other fatty substances that were carried in with the supercritical CO2. This then allows you to separate the CBD and make it into a pure, CBD-only oil.

If all that is too much trouble for the manufacturer, there is another method available for CO2 extraction that is rather cheaper and easier, but has more problems associated with it.

Subcritical CO2 Extraction

Now that we know about supercritical CO2 extraction, we can look at subcritical CO2 extraction.

Essentially, subcritical CO2 extraction is a similar process to supercritical but, as the name implies, subcritical does not heat the CO2 to the levels that allow it to enter into a supercritical state.

Instead, what happens is the CO2 diffuses a large number of compounds alongside the target CBD, due to the fact that it doesn’t have the same properties as both a gas and a liquid that supercritical CO2 has.

This results in a finished product that has the consistency of thick syrup, thick because of the intensity of different compounds present within the finished oil. This can mean that the THC within cannabis is carried with the CBD over to the finished oil, resulting in a non-pure CBD oil.

This is actually perfect if you intend to create marijuana oil containing both THC and CBD, but for the purposes of legality, it is imperative that CBD oil contain less than 0.3% THC to be able to be sold nationwide.

As such, further methods need to be employed to make sure the CBD oil is legal and THC-free. The big benefit of this method is that it is cheaper to produce, as well as not requiring the winterization process that supercritical extraction needs.

Final Thoughts on CBD Oil CO2 Extraction

CO2 extraction for CBD oil is an incredibly useful process, one that allows manufacturers to produce pure CBD oil from a plant that contains many other compounds they might not necessarily want to include in their final product. With the help of some very expensive equipment and heated and pressurized CO2, a manufacturer can make something completely separate from the cannabis plant, all while still being a natural ingredient to help people’s health.

The age old question of which is superior, subcritical or supercritical, has no real answer, as different manufacturers argue constantly.

However, some manufacturers combine these two processes into something called full spectrum CO2 extraction, which uses a multi-chambered extraction process with both supercritical and subcritical CO2. By using supercritical to separate the oil, then subcritical to further separate the crude oil, manufactures are able to completely control the method and temperature with which the CBD is extracted, allowing for more control of the finished product. Of course, this is also obscenely expensive to setup.

All in all, there’s a reason why you buy CBD oil from a retailer instead of making it yourself; some things are just too hard to do alone.

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