CO2 extraction is a popular method for creating THC distillate for cartridges and edibles. Releaf Labs lab director Ariel Parson shows how it is done.
Vape pens are ubiquitous in cannabis culture, with their popularity now rivaling that of raw cannabis flower. Many labs use a process known as supercritical CO2 (carbon dioxide) extraction to create their distillate for cartridges and edibles.
This solvent method contains a number of steps and utilizes several pieces of specialized equipment to process the distillate.
Releaf Labs gave Extract a tour of its facility, and lab manager Ariel Parson spoke about each step of the process in its labs, which he estimates contain about $1 million in equipment.
Each production run is between 10 and 20 pounds. Releaf Labs was conducting two runs a day at that time.
1) The first step is decarboxylating the flower, or heating it for a length of time in an oven.
“For our extraction purposes, we turn THCA (tetrahydrocannabinolic acid) into THC, which will then be processed through our CO2. THCA is not psychoactive. It has to be activated to turn into THC. So we decarb the material,” Parson said. “It also helps lower the humidity of the material before it goes into the CO2 extractor because water carries over chlorophyll, which will give the distillate a darker appearance.”
2) “We put that decarbed material into the CO2 extractor, and what that does is pass CO2 through the decarbed material to create what we call crude oil. It is CO2-extracted plant material. We normally do supercritical, which is low pressure, high heat. And that’s going to pull some of the fattier cannabinoids out,” Parson said. “1A is going to be our separator tank. That’s where we collect our crude oil. 2A would be the overflow vessel; basically any oil that carries over will be caught in that one so it does not go into the CO2 compressor and cause a clot or anything. After we have our crude oil, we then have to winterize our crude oil to get the fat separated. And so it goes to the freezer first, to pull the fats away. And then we filter and then it goes to the Heidolph.”
3) “The Heidolph is evaporating the ethyl alcohol from the crude oil and ethyl mixture, so we mix ethyl with the crude oil to separate the fats and then we filter out the fats and then also evaporate out the alcohol and we’re left with winterized oil,” Parson said. “The Heidolph evaporates the ethyl out of it, so that’s the same as winterizing. You don’t necessarily have to get it as cold as we get it. It just speeds the process up.”
4) Next, it goes into the purge oven.
“That is to remove any remaining ethyl and also any lighter terpenes and anything like that that’s going to bubble off in the vacuum of it,” Parson said.
5) “From there, we go to short-path distillation. Distillation is where we separate the THC and other cannabinoids from the terpenes and the heavier cannabinoids and other plant material, whatever’s left in the winterized oil. First, we distill what we call the head, and that’s going to be terpenes and aromas, the stuff that really gives the smell and the character to the material. And then we have our body, which is the raw distillate that we use to make our carts, and then the tail is going to be any post-distillate run, so any of the heavier cannabinoids will be in the bottom of the heating glass when we’re finished. It’s similar to an alcohol distillery.
“Our last and final step before packaging is terpene infusion. Because we distilled all of the terpenes out of the distillate, we then have to reintegrate those terpenes to give it a flavor because raw distillate does not taste very good.”
The terpenes are re-added using stirrers, and then the distillate is ready to be packaged.
6) “This is our 710 Shark. This allows us to fill 100 carts simultaneously,” Parson said. “We have an oil basin down here that is heated and then also this injector head that is also heated. We can do our disposables or one-gram carts over here as well.”
Once capped, the distillate cartridges are ready to hit dispensary shelves for patient consumption.