Decarbing (short for decarboxylation) is the process of heating cannabis to convert its raw, inactive compounds into the active forms that produce effects. Raw cannabis contains THCA and CBDA, acidic precursors that don’t get you high or deliver the full therapeutic benefits of THC and CBD. Applying controlled heat removes a chemical group from these molecules, releasing carbon dioxide and leaving behind the active cannabinoids your body can use.
This step is essential for anyone making edibles, tinctures, or infused oils. Smoking and vaping handle decarboxylation instantly through combustion, but if you’re cooking with cannabis, you need to do it yourself first.
Why Raw Cannabis Doesn’t Work in Edibles
The cannabis plant produces cannabinoids in their acidic form. THCA, the precursor to THC, has an extra carboxyl group attached to the molecule. That group makes it too bulky to bind effectively to the receptors in your brain that produce a high. CBDA, the precursor to CBD, works the same way. Until heat knocks that carboxyl group off, these compounds remain largely inactive for the purposes most people care about.
When you decarb, you’re breaking that chemical bond. The carboxyl group detaches and floats away as CO₂, leaving behind a smaller, active molecule. This is why eating a raw cannabis bud won’t produce the same effect as eating a properly made edible. The conversion needs to happen before the cannabinoid enters your digestive system.
One detail worth knowing: this conversion causes a small loss in weight. THCA is about 12-14% heavier than THC because of that extra chemical group. So if you start with flower that tests at 20% THCA, you won’t end up with 20% THC by weight. The actual THC yield is roughly 87.7% of the original THCA weight (you multiply by 0.877 to account for the lost CO₂). This matters if you’re trying to calculate the potency of homemade edibles.
Temperature and Time: The Key Variables
Decarboxylation is a balancing act between enough heat to activate cannabinoids and too much heat, which destroys them. Research using pure THCA found that temperatures below 100°C (212°F) couldn’t finish the conversion within 60 minutes. At 110°C (230°F), the THCA concentration dropped to nearly zero in about 30 minutes. At 130°C (266°F) it took only 9 minutes, and at 145°C (293°F) just 6 minutes.
Faster isn’t better here. Higher temperatures accelerate a second, unwanted reaction: THC breaking down into CBN, a cannabinoid associated with sedation rather than the typical THC effects. At 200°C (392°F), nearly 30% of degraded THC converts into CBN. Even at 120°C to 160°C, some CBN formation occurs, though at much lower rates (around 8-9% of degraded THC). The sweet spot is a temperature high enough to complete decarboxylation in a reasonable time but low enough to minimize this degradation.
For most home methods, that sweet spot falls between 220°F and 250°F (105°C to 121°C), with cook times ranging from 20 minutes to 60 minutes depending on the exact temperature and method you choose.
The Standard Oven Method
The most common approach is simple: use your kitchen oven. Here’s how it works.
Preheat your oven to 250°F (121°C). While it heats, break your cannabis into small, pea-sized pieces by hand or with a grinder. You don’t want a fine powder, which heats unevenly and becomes difficult to strain later. Spread the pieces in a single layer on a parchment-lined baking sheet.
Bake for about 20 minutes. When finished, the cannabis should look golden brown. Remove the baking sheet and let it cool completely before handling. The material will be dry, fragile, and crumbly at this point. Once cool, you can grind it finer if needed and use it immediately in recipes or store it in an airtight container.
The biggest drawback of this method is oven temperature fluctuation. Most home ovens cycle on and off to maintain their set temperature, which can create swings of 10 to 20 degrees in either direction. An oven thermometer placed next to your baking sheet helps you verify you’re staying in the right range. The other downside: it produces a strong smell throughout your home.
The Mason Jar Method
If odor is a concern, the mason jar method contains most of the smell inside the sealed glass. Set your oven between 220°F and 240°F and place the rack in the middle position. Break the cannabis into rice-grain-sized pieces and place them in a mason jar, screwing the lid on loosely (tight sealing risks pressure buildup).
Place a damp kitchen towel on a baking sheet to anchor the jar and prevent it from tipping, then set the jar on top. Bake for 60 minutes, removing the jar with oven gloves every 15 minutes to give it a gentle shake. This redistributes the cannabis for more even heating. After the full 60 minutes, remove the jar and let it cool for at least 30 minutes before opening.
The lower temperature and longer time in this method reduce the risk of overshooting, and the sealed environment traps volatile compounds inside the jar rather than venting them into your kitchen.
Sous Vide: The Most Precise Option
A sous vide immersion circulator offers the tightest temperature control of any home method. Set the water bath to 203°F (95°C). Place your cannabis in a heat-safe plastic bag, press out all the air, and seal it. Submerge the bag and hold it at temperature for 90 minutes.
The main advantages are consistency and safety. Water temperature stays rock-steady with no cycling, and because the maximum possible temperature is the boiling point of water, it’s physically impossible to burn your material. The sealed bag also eliminates virtually all odor during the process. The tradeoff is a longer cook time due to the slightly lower temperature compared to oven methods.
What Happens to Terpenes
Terpenes are the aromatic compounds responsible for cannabis flavor and scent, and many of them are more fragile than cannabinoids. Some have boiling points that overlap with common decarbing temperatures. Beta-caryophyllene, for example, begins to boil at around 130°C (266°F), while alpha-pinene reaches its boiling point at 157°C (315°F) and myrcene at 172°C (342°F). Limonene boils at 178°C (352°F).
At the recommended decarbing range of 220-250°F (105-121°C), you’re generally below the boiling points of most terpenes. But some loss still occurs, especially with the most volatile ones, because evaporation begins well before the boiling point is reached. Sealed methods like mason jars and sous vide bags help retain more terpenes by trapping vapors inside the container rather than letting them escape into the air. If you’re making something where flavor matters, like an infused butter or oil, a sealed method is worth the extra effort.
Avoiding THC Degradation
The most common mistake in decarbing is overheating or heating for too long. THC doesn’t just sit there patiently once it’s been activated. It continues to break down, primarily into CBN. This degradation happens slowly at moderate temperatures but accelerates significantly above 300°F (150°C).
Long-term storage also matters. Research tracking cannabis samples over four years found that nearly 100% of THC degraded under certain storage conditions, with CBN accumulating in its place. Heat, light, and air all speed this process. Once you’ve decarbed your cannabis, store it in an airtight container in a cool, dark place. If you’re making an infused oil or butter, the same storage principles apply to the finished product.
The practical takeaway: decarb at the lowest effective temperature, stay within the recommended time window, and don’t assume that extra time in the oven will squeeze out more potency. Beyond the point of full conversion, you’re only losing THC.