Does CO2 Extraction Kill Mold?

CO2 (Carbon Dioxide) has many uses, ranging from dry cleaning to extracting cannabis! In the process, it also helps mitigate certain issues with the plant material, like mold. However, it is extremely important to note that processing moldy material is not recommended, under any circumstances! The bacteria found along with mold can be harmful, even in miniscule amounts. Using the CO2 method of extraction should not be used as a mold mitigation tactic. Healthy source material is key to producing high quality products.

Mold is just one hazard to watch out for. Plant material can contain heavy metals pulled from the earth (especially in hemp, which tends to “clean” the earth it’s planted in), pesticides, and other bacteria. Testing the plant material is crucial to ensure a safe product.


Does Butane kill mold?

Like CO2, butane will kill mold at supercritical parameters, but again, using moldy source material is not recommended!


How does CO2 Oil Extraction Work?

CO2 is a powerful solvent when passed over plant material at high pressure/high temperature. Apeks Supercritical manufactures closed loop CO2 extraction systems that allow users to process large amounts of cannabis and hemp to extract the essential oils from the plant, creating concentrated oil. The oil can be used in a wide variety of products, like vape pens, edibles, and infused products. Unlike other solvents, CO2 leaves no trace behind so is considered a safe and pure method of extraction, which is why it’s especially important to use clean source material. Why use a clean extraction method when your plants are moldy?


Does CO2 extraction remove terpenes?

One thing CO2 really excels at is fractioning terpenes. Operators run their machine using subcritical parameters to pull the sensitive terpenes. This may take a few minutes, or half an hour: it depends on which system is used. The terpenes are harvested and set aside. Despite not being cannabinoids, these terpenes contain benefits that are highly desirable. Once the rest of the oils are extracted from the plant and refined into pure oil, the terpenes are reintroduced, creating a full spectrum oil. 


How does CO2 oil extraction work?

When used at high pressure and high temperature, CO2 is a powerful solvent. Here is a four-step walkthrough of how it works with an Apeks Supercritical system.

Step 1: The operator loads the extraction vessel with dried, ground up plant material and ensures that all seals are correctly tightened. He or she will begin the operation (and Apeks systems are fully automated so once the parameters are set, the system will run by itself), and the Extraction Vessel begins filling – see diagram 1.

Diagram 1: Filling the Extraction Vessel:


Step 2: Once sealed, the system begins to pressurize. It will pressurize up to the PSI set by the operator at the system start up. The diaphragm compressor on most Apeks systems pushes the flow of CO2 through the system. See Diagram 2.

Diagram 2: Pressurizing the system: 


Step 3: The flow of CO2 passes over the plant material while it’s under pressure and pulls the oil from the cannabis. Then it passes through to the Separator vessel where it flows through an orifice which depressurizes the flow and causes the oil to drop out of the CO2 stream. See Diagram 3.

Diagram 3: Extracting the oil

Step 4: The stream of CO2 continues in the closed loop system until the run is complete (parameters – time/pressure/temperature are set by the operator at the start so the system runs until it achieves those numbers) before it goes into the recovery phase. The CO2 flow (minus the oil, which is left behind in the collection cup) is recovered back into the CO2 cylinders. Apeks systems recover up to 95% of the CO2. See Diagram 4.

Diagram 4: The system goes into recovery

Components of an Apeks system

What is Subcritical CO2 extraction? 

Subcritical is when parameters are set below 1083psi and 88F, which are considered low pressure and low temperature. During this phase, terpenes are extracted and harvested, then set aside for use with the rest of the oil. The subcritical run continues, extracting cannabinoids, before the run finishes. Some post processing work is needed to refine the extract.

What is Supercritical CO2 extraction? 

Supercritical is high pressure and high temperature and extracts the rest of the components from the plant, including fats, waxes and lipids, which are usually filtered out of the extract in a post processing technique called Winterization.

What is Winterization?

Winterization is when the fats, waxes, and lipids are removed from the crude oil extract. This is done by adding ethanol (200 proof) to the mixture and mixing it until it’s fully homogenized. The mixture is placed in a deep freezer overnight and then run through a filter. This removes the undesired elements but the ethanol still needs to be removed from the oil. This is done using a rotary evaporator, which uses heat to gently remove the alcohol from the oil. After that, the terpenes can be added back to the winterized oil, for a full spectrum product.

Is CO2 extraction healthy?

This goes back to the question in the beginning about mold. Yes, CO2 extraction is healthy because it leaves no residue, but if contaminated source material is extracted, that contamination will carry through to the extract, and not only that, it will be concentrated. We recommend testing the source material at an independent laboratory before and after an extraction. Before, to ensure that there are no contaminants in the plants, and after because there might have been undetectable amounts of contaminants in the source material which are now concentrated and detectable. Unfortunately, there is no oversight in the cannabis and hemp industries and similar to the supplement industry, producers can make all kinds of claims about the contents of the bottle, without having to prove it. It is always a good practice to request a laboratory certification to ensure the cleanliness of the product, and also, to ensure that what’s on the label is what’s in the bottle.

What are the Pros and Cons of CO2 Extraction?

A large pro of CO2 is that it’s considered a safe and pure extraction method. This is because it simply bubbles out of the extract upon completion – similar to an open soda bottle which goes flat once it’s decarbonated. This means that no peripheral safety equipment is required and also helps with license applications. CO2 is not explosive or flammable, and in some regions other solvents, like butane, are banned.

CO2 is also very efficient at fractionation, or selectivity. The solvent is very tunable and what that means is that the user can set the parameters to extract only the components they need, for example, terpenes. Other methods of extraction, like ethanol (alcohol) simply pull everything out in one wash without being able to differentiate between terpenes and cannabinoids.

CO2 equipment is costly; at the same time, since no peripheral safety equipment is required, it might balance the cost of a cheaper extraction unit, that requires expensive housing.

Finally, CO2 is slower than other methods, like ethanol. However, if operators add a co-solvent injection module, such as the one Apeks Supercritical sells, the speed improves drastically!

What are the Pros and Cons of Ethanol/Alcohol?

The equipment cost is relatively low for ethanol systems while the yields are high. However, the solvent is flammable, but not explosive, so some safety precautions and peripheral equipment is needed. Not as much as butane though, which requires a full C1D1 safety protocol in place.

What are the Pros and Cons of Hydrocarbons (Butane)?

Like ethanol, butane has low equipment cost and high yields. This is most definitely offset by high safety equipment cost. Even if the butane system is a closed loop system, the safety equipment is needed because this is an explosive solvent. In the US, some cities have banned butane outright, even if the system is closed loop.

Both ethanol and butane are not great at extracting terpenes. Butane is better than ethanol, but ethanol simply washes straight through the material and extracts everything in one extraction.

For more information, please check out our systems or contact us!

31 Greenscape Court

Johnstown, OH 43031


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