Generally speaking, decarboxylation is just a chemical reaction that releases carbon dioxide as it removes a carboxyl group. Most commonly, decarboxylation removes a carbon atom from a carbon chain in a carboxylic acid reaction.
But the reason most cannabis consumers need to know about decarboxylation is contextual: that reaction is what makes many cannabinoids active and usable for humans. This is why applying heat while smoking or vaporizing is an essential step in consuming cannabis and cannabinoids and in understanding dosing.
Read on to learn what decarboxylation is, what the connection between cannabis, cannabinoids, and decarboxylation is, and why it’s so important to decarb your weed—especially if you’re making edibles.
Cannabinoids and Decarboxylation
You must decarboxylate, or “decarb”, your cannabis flower before eating it. Skipping this step produces an inactive or weak result. When you smoke cannabis flower or dab cannabis concentrates, the heat from the flame does the job for you, activating the cannabinoids—although if you decarb your flower in advance, it will be more potent.
The reason is that heat activates many cannabinoids so they can bind with the receptors in the endocannabinoid system.
The full spectrum of cannabinoids naturally occurs in raw cannabis flower, but neither CBD nor THC occurs in high amounts. However, raw cannabis does contain high levels of cannabinoid acids CBDA and THCA, which heat converts into CBD and THC, respectively. This is why vaping or smoking cannabis produces euphoria and other effects.
The natural plant chemicals cannabinoids produced in the trichomes are most famous for tetrahydrocannabinol (THC), the compound that lends cannabis its psychoactive effects. Cannabidiol (CBD) is also becoming more well-studied. Yet beyond THC and CBD, there are at least 100 distinct cannabinoids in the Cannabis sativa plant, which produce a broad spectrum of effects.
Here is how cannabis decarboxylation produces cannabinoid compounds from cannabinoid acids (with each arrow representing the decarb process).
CBGA (Cannabigerolic acid) breaks down after decarboxylation into THCA, CBDA, CBCA, and CBG, with a small amount of CBGA remaining:
CBGA (Cannabigerolic acid) —> THCA (Δ9-tetrahydrocannabinolic acid)
CBDA (Cannabidiolic acid)
CBCA (Cannabichromenenic acid) —> [remaining CBGA] —> CBG (Cannabigerol)
Then further decarbing takes place as non-intoxicating THCA converts into THC:
THCA (Δ9-tetrahydrocannabinolic acid) —> THC (Δ9–tetrahydrocannabinol)
As the cannabis plant matter dries, the THCA found in raw, live cannabis converts gradually to THC. Decarboxylation expedites the conversion with heat. It also produces CBD from CBDA, and CBC from CBCA:
CBDA (Cannabidiolic acid) —> CBD (Cannabidiol)
CBCA (Cannabichromenenic acid) —> CBC (Cannabichromene)
The process affects other minor cannabinoids as well:
CBCVA (Cannabichromevarinic acid) —> CBCV (Cannabichromevarin)
CBDVA (Cannabidivarinic acid) —> CBDV (Cannabidivarin)
CBGVA (Cannabigerovarinic acid) —> CBGV (Cannabigerivarin)
THCVA (Tetrahydrocanabivarinic acid) —> THCV (Tetrahydrocannabivarin)
Over a period of time and with oxygen exposure, THC gradually decomposes into CBN.
How to Decarb Cannabis
Can you just smoke or vape cannabis flower without decarbing? Sure! You already have, right? But it’s more potent and goes further if you decarb first. If you are making something like RSO or a tincture, there may be a reason to work with raw cannabis plant material, but otherwise you will usually decarb first. And if you’re making cannabis edibles, activated THC is a must.
If you are making edibles, and what you’re making is cannabutter, can’t you just directly infuse cannabis into the butter or oil over lower temperature? Yes, it’s possible to decarb cannabis directly in the hot butter, but it’s better to decarb first because it’s faster and for the sake of the final product’s taste.
That’s because when you decarboxylate first in the oven or a device it minimizes the time the cannabis spends soaking in your tasty food. It lets you skip a step to decarb while you infuse, but it also lets more chlorophyll into the infusion and makes infusion itself take longer, producing a greener flavor in the butter or other food.
If you have a device like an Ardent Nova, it’s simple: you pretty much follow the instructions and wait for it to decarb.
To decarboxylate your cannabis in the oven:
Preheat your oven to 240-245 degrees Fahrenheit (around 120C). Cover a rimmed, oven-safe baking sheet with parchment paper. Distribute cannabis buds evenly on the tray and place the tray in the oven.
Every 10 minutes or so, remove the tray and shake it gently to mix up the buds. You are aiming to expose the surface area of the buds equally to heat as time passes. Check every 10 minutes, and expect to bake the cannabis for a total of 30 to 40 minutes. Old, dry cannabis may take less time.
You will see physical signs of the process of decarboxylation as you check on your cannabis such as a color change to a darker, more brownish-green from a more vivid green.
Some people speed the decarboxylation process and heat at 300ºF for only 10 to 20 minutes, but this is risky and high temperatures just don’t always work. To maximize your cannabinoids and minimize risk, the slow and steady approach is always better.
Once the heating part is over, you can grind the decarbed flower coarsely, a bit like dried parsley. Use a hand grinder for this. Now it’s ready for infusing with butter or oil as directed by your recipe.
Infusion temperatures are different, so keep this in mind as you move past decarboxylation and toward infusion. A steady temperature between 160 and 200°F is essential to steeping ground cannabis in fats. The sous vide method is most precise, but a double boiler is safer on the stovetop. For a slow cooker, this is usually the low or medium setting.
Whichever method you select, make sure you stay at the right temperature by using a thermometer when you’re in the right zone. Infuse there for about three hours.
To sum up:
- Preheat the oven to 240-245°F
- Spread cannabis—no need to grind yet—on a cookie sheet lined with parchment paper
- Heat in the oven for about 1 hour, stirring gently every 10 to 15 minutes
- Grind by hand after decarboxylation
Remember, to get the right results, you need to maintain the right temperatures, both during decarboxylation and during infusion, for the right amount of time. It is a rookie mistake to use the wrong temperature, especially to rush things at heat that is too high.
In general, to decarboxylate cannabis: About 240°F (about 120°C) for 50 to 60 minutes while stirring every 10 to 15 minutes is going to be in the right zone. Remember, you need to keep it from getting too hot to avoid destroying cannabinoids and terpenes in the final product.
Some people heat for about 20 minutes at 300°F (150°C) stirring more often—about every five minutes—to save time, but this is far less reliable for decarboxylation reactions.
Final Thoughts on Decarboxylation
Cannabis works harder when you can access all of the good stuff that naturally occurs in it! Decarboxylation is really just the scientific way of describing applying slow and steady heat to make sure your body can access those cannabinoids.