The purpose of CBD extraction is quite simple; to end up with the cannabinoid (and others) in a highly concentrated form to make it suitable for human consumption.
To achieve this, you must use a plant material rich in CBD such as special cannabis strains or hemp. Special cannabis strains such as AC/DC and Charlotte’s Web have a high CBD concentration (up to 18% in some cases) and a low THC concentration (as little as 5%). You need a favorable CBD/THC ratio because even in cases where plants have a THC concentration of up to 6%, the extra high CBD content should hopefully render the psychoactive effects of THC inert.
Industrial Strains and Extraction
Various strains of industrial hemp can also be used to extract CBD. They are grown around the world legally; including in India, China and several countries in Western Europe. One of the most popular industrial hemp strains is Fedora 17. It has a low THC content which means any CBD extracted from it should have no psychoactive effects.
Hemp Oil made from hemp is legal in almost every country around the world including in all 50 states in the U.S. because of the negligible THC content.
Without further ado, let’s look at the 4 most common CBD extraction methods:
CBD Extraction Methods:
1 – The CO2 Cannabis Extraction Method
This form of CBD extraction is actually divided into supercritical, subcritical and ‘mid-critical’ categories but supercritical is by far the most commonly used. In fact, it is the most regularly used extraction method of all because it is safe and provides a pure end product.
In simple terms, CO2 cannabis extraction uses pressurized carbon dioxide (CO2) to pull CBD (and other phytochemicals) from the plant. CO2 acts like a solvent at certain temperatures and pressures but possesses none of the dangers. While it is safe and effective, it also involves expensive equipment that freezes the CO2 gas and compresses it into a supercritical cold liquid state.
CO2 & Extraction
CO2 typically behaves like a gas at standard pressure and temperature, and is easily changed to a solid while in this state; the solid version of the gas is known as dry ice. Using the aforementioned equipment in a lab, you can turn CO2 gas into a liquid by ensuring the temperature drops below -69 degrees Fahrenheit while increasing the pressure to over 75 pounds per square inch (psi). At this stage, you have your starting point for CO2 Cannabis extraction.
Once you have the liquid CO2, the next step is to increase the temperature and pressure past the point where the liquid becomes ‘supercritical.’ This term means the CO2 is now capable of adopting properties halfway between a gas and liquid simultaneously. Effectively, the supercritical CO2 is capable of filling a container (like gas) while also maintaining density (like a liquid). When CO2 is in its supercritical state, it is ideal for chemical extraction because it won’t cause the denaturing or damage that would make the CBD unfit for human consumption.
Liquid CO2 and The Extraction Process
Regarding extracting the Hemp Oil using this technique, you simply begin with liquid CO2 and raise its pressure via a compressor. You must also raise its temperature using a heater. The next step involves passing the supercritical carbon dioxide through some high-quality cannabis. Now, the CO2 will pull the essential trichomes(the sugary looking coating of the cannabis plant) and terpene oils (essential oils) out of the plant.
The solution gets passed via a separator and is broken down into its requisite parts. The good stuff (including trichomes and terpenes) is sent to the collection container. Meanwhile, the supercritical CO2 goes through a condenser and is turned back into a liquid. Finally, the liquid goes to a special storage tank and can be used to begin the process all over again.
This form of extraction involves low temperatures and low pressure. Subcritical extractions take longer than their supercritical counterparts and also produce a smaller yield. While it retains the terpenes, essential oils and other sensitive materials, it doesn’t extract larger molecules such as chlorophyll and omega 3 and 6. The benefit of subcritical extraction, however, is that it is less likely to damage terpenes.
Mid-critical is simply a general range between subcritical and supercritical. Some companies combine supercritical and subcritical to create a full-spectrum CO2 cannabis extract. They use the subcritical extraction method to separate the drawn-out oil and draw out the very same plant material using supercritical pressure. The oils are then homogenized into one which creates an amalgamated oil. This is known as the CO2 Total Extraction Process.
Pros and Cons of CO2 Cannabis Extraction
|Pros||Safety: CO2 is a common food additive and is used to produce things like carbonated soft drinks.||Effectiveness: CO2 has been used as an extraction solvent for years by food companies. It is used to remove caffeine from coffee and as an extraction solvent when producing essential oils.||Purity: The cannabinoids produced are potent and free of chlorophyll with minimal risk of contaminants.|
|Cons||Expensive: You can only complete the process with the aid of extremely expensive equipment.||Technical Ability: CO2 Cannabis extraction is not something that should be attempted by an amateur chemist.|
2 – The Olive Oil Extraction Method
The first step in olive oil extraction, which can be performed at home, involves ensuring the raw plant material is decarboxylated. In layman’s terms, it means you have to heat the plant to a certain temperature for a specific length of time to activate the plant’s chemicals.
Most experts recommend heating at 248 degrees Fahrenheit for 60 minutes or at 284 degrees Fahrenheit for 30 minutes. Once this step is completed, plant material is added to the olive oil and heated to 212 degrees Fahrenheit for up to 2 hours (and at least 1 hour). This process should result in the extraction of cannabinoids.
Pros and Cons of the Olive Oil Extraction Method
|Olive Oil Comparison||1||2|
|Pros||Very Safe: This method has been deemed safe and effective||Inexpensive: You can set everything up at home without breaking the bank.|
|Cons||Perishable: Regardless of whether your cannabis-infused oil is high in CBD or THC, it is highly perishable so you must store it in a cool, dark place and use as soon as possible.||Low Yields: This form of extraction only produces fairly low yields.|
3 – The Dry Ice Extraction Method
The dry ice extraction method is another method of CBD extraction that can be performed at home, although it takes a bit more time and effort than its olive oil equivalent. As well as the cannabis plant itself, you’ll need the following equipment:
- Around 3 pounds of dry ice
- A large piece of Plexiglas or a mirror
- A paint scraper or putty knife
- Thick gloves that are heat resistant and eye protection
- A clean 5-gallon plastic bucket
- 3 bubble hash mesh bags; sizes are 73, 160 and 220 microns
- 3 large, clean glass jars for storage
Put on your gloves and eye protection, chop up the cannabis plant into small pieces and place it in the bucket. Cover the plant with the dry ice and leave it for 3 minutes. It is best only to fill the bucket halfway. This process causes the freezing of the trichome resins. Fit the 73-micron bag over the bucket and shake the ice & plant combo for about 4 minutes; this knocks the frozen trichomes off.
Turn the bucket upside down on the Plexiglas and shake as much resin through the mesh bag as possible. Scrap the hash off the Plexiglas with your scraper and place it into one of the jars. Repeat with the 160 and 220-micron mesh bags, and you’ll be rewarded with three different strains of extract.
Pros and Cons of the Dry Ice Extraction Method
|Dry Ice Comparison||1||2||3|
|Pros||Ease of Use: The steps above are very easy to follow.||Clean: Unlike other methods, there is very little mess with dry ice extraction.||Decent Yield: You’ll end up with a lot more than if you use oil extraction.|
|Cons||Low-Quality: This is entirely dependent on the user, but you will ruin the quality of the product if you shake it for too long.||Not Always Easy Getting Dry Ice: Depending on where you live, it isn’t always so easy to get your hands on 3 pounds of dry ice unless you order it online.|
4 – The Solvent Extraction Method
Ethanol, low-grade alcohol, and butane are among the most common substances used in solvent extraction. Although ethanol extracts the full range of cannabinoids and terpenes from the plant, which makes the end product safe for consumption, it also extracts chlorophyll which may lead to some unpleasant side effects.
You can remove the chlorophyll by filtering the extract, but you significantly reduce the oil’s potency. Butane offers a stronger oil than ethanol, but it is more likely to contain solvents that could irritate the lungs.
For extraction, the liquid is added to the plant material. The extraction liquid will strip away the cannabinoids and flavor from the plant material but will probably take some green colorings too. Once enough cannabinoids have been extracted, heat the liquid to evaporate it down to the CBD base oil.
Pros and Cons of the Solvent Extraction Method
|Pros||Appropriate For Some Products: If you use high-grade alcohol, you may produce good quality oil.||Straightforward Process: Once you have the equipment, it isn’t difficult to complete.|
|Cons||Extremely Dangerous: Butane and Ethanol are flammable, so it isn’t worth starting a fire in your home to extract CBD in this manner.||Potentially Harmful: As well as destroying plant waxes, this form of extraction may produce oil that contains chlorophyll or other harmful contaminants.|
Final Words About CBD Extraction
It is extremely important to understand the various CBD extraction methods as they have a major impact on the quality of the end product; not to mention your health. We don’t recommend utilizing the solvent method because not only is it dangerous to make, it is also more likely to cause health problems. The cost of CO2 supercritical extraction means it is not possible for 99.9% of readers, but it is an excellent, safe and efficient method. Those who create their own CBD oils will tend to use dry ice or olive oil, which provide great purity and are easy to do. There are also other extraction methods that we have not mentioned in this guide.