The CO2 Cannabis Extraction Method Explained

Cannabis plant (hemp and marijuana) products have dominated the health and wellness scene for the last decade. The plants contain numerous phytochemicals that research has established have multiple therapeutic benefits. These compounds include cannabinoids (THC and CBD being the most abundant), terpenes, flavonoids, and essential oils. Cannabis products are available in various forms: flowers, edibles, and extracts. The oil extracts are the center of the booming hemp sector, thanks to the diversity they offer. Extracts can be vaped, dabbed, added to joints, mixed with carrier liquids to make oils and tinctures, or added/made into topicals. 

So, how are cannabis extracts made? When surfing the internet, you will encounter a list of methods used to extract phytochemicals. The list includes the CO2 supercritical extraction method, solvent extraction, olive oil extraction, steam distillation, etc. This piece, in particular, focuses on CO2 extraction. Compared to the other extraction methods, CO2 produces the purest, cleanest, and safest product called CBD crude oil. 

What makes CO2 the ideal gas to use?

CO2 is a special gas that reaches a supercritical state when exposed to a pressure of 1071 psi and temperatures of 31.1°C concurrently. At this state, CO2 possesses qualities of liquid and gas and can easily bond with multiple molecules. CO2 is non-toxic and evaporates when exposed to room temperatures in case some of it is left behind after the extraction process. This makes it an ideal candidate to use in extracting hemp compounds.

The CO2 extraction technique is divided into supercritical, mid-critical, and subcritical. The first technique is the most utilized and is the fastest. Below is a step-by-step procedure of how cannabis compounds are extracted using the CO2 supercritical extraction method.

How does the CO2 extraction method work?

The CO2 extraction equipment comes in different sizes depending on the size of the operation/size of the batches being made. Some of the equipment is automated, meaning that the process runs smoothly with minimal intervention from the producer, while others work manually. This technique utilizes pressure and temperature fluctuations to extract phytochemicals from cannabis plants. 

Step 1

Hemp is harvested and dried. The CO2 extraction method requires completely dried hemp material since it doesn’t do well with water as it leads to a lower yield. The hemp flowers are ground into fine particles and put in the extraction vessel.

Step 2

CO2 is pushed into the vessel containing the ground hemp flower by a pump and exposed to specific temperatures and pressure, turning it to liquid form. Here, CO2 breaks down the trichomes and absorbs some of the oil as it passes through before being pushed by a release valve into another chamber. CO2 in liquid form is an excellent solvent that is able to extract phytochemicals rapidly. 

Step 3

In the next chamber, CO2 is depressurized to convert it into a gaseous state. As a result, all the compounds picked in the previous chamber are dropped into a collection beaker. The CO2 then goes back to the extraction vessel, and the process continues in a loop until all the compounds have been extracted. 

What happens after the extraction process?

The CO2 supercritical extraction process produces what is referred to as CBD crude oil. This is a dark-hued, highly potent (about 50% CBD) product containing a host of phytochemicals, such as cannabinoids, terpenes, flavonoids, lipids, fat, and wax. CBD Crude oil can be consumed by adding it to food, placing it under the tongue, applied topically, or made into capsules. The extract has multiple therapeutic applications, such as stress relief, pain management, combating nausea and vomiting, treating neurological conditions such as epilepsy, and reducing PTSD symptoms.

Further processing of CBD crude oil

The crude oil can be further processed to create full-spectrum, broad-spectrum, and isolate CBD products. First, the crude oil undergoes winterization to eliminate fats, lipids, and waxes. This involves mixing the oil with ethanol and mixing the two compounds using a hot plate. The mixture is placed in a freezer for 24 to 48 hours and then poured into a vacuum flask with a filter where the fats, lips, and waxes are filtered out. To remove the ethanol, the flask is placed in warm water. The ethanol gradually evaporates, leaving behind a dark brown oil.

The oil then undergoes decarboxylation to activate the cannabinoid and distillation to create pure full-spectrum CBD. The product contains all the compounds found in hemp, except for fats, lipids, chlorophyll, and wax. The demand for full-spectrum CBD is significantly high due to the entourage effects it offers. It is scientifically proven that the phytochemicals work in synergy to produce heightened therapeutic benefits  – more intense than what one would get from taking a compound/isolate on its own. To get broad-spectrum CBD, the oil is subjected to selective distillation. Pure CBD can be further extracted from a full-spectrum oil through short path distillation.