Decarboxylation is the process that activates compounds in cannabis such as THC. All cannabinoids contained within the trichomes of raw cannabis flowers have an extra carboxyl ring or group (COOH) attached to their chain. For example, tetrahydrocannabinolic acid (THCA) is synthesized in prevalence within the trichome heads of freshly harvested cannabis flowers. In most regulated markets, cannabis distributed in dispensaries contains labels detailing the product’s cannabinoid contents. THCA, in many cases, prevails as the highest cannabinoid present in items that have not been decarboxylated (e.g., cannabis flowers and concentrates).
THCA has a number of known benefits when consumed, including having anti-inflammatory and neuroprotective qualities. But THCA is not intoxicating, and must be converted into THC through decarboxylation before any effects can be felt.
Decarboxylation is the magic that makes cannabis a potent additive to food.
Simply put, it’s a chemical reaction that is achieved through heating up raw cannabis to a temperature at which it releases a carboxyl group and becomes psychoactive.
THCA (Tetrahydrocannabinolic acid) is the active component in raw cannabis, and it’s not a psychoactive compound by default.
Through decarboxylation, we’re essentially applying heat to plant material so that the THCA gets converted to THC, enabling us to get high.
What is Decarboxylation?
Think of decarboxylation (also known as “decarbing”) as activating raw cannabis into an enhanced potent form. In more scientific terms, decarboxylation is the process of physically altering the chemical structure of various cannabinoid compounds found in raw cannabis plants – including both marijuana and hemp.
When a cannabis plant is growing or freshly harvested, the cannabinoids found within the flower trichomes contain an extra carboxyl ring or group (COOH) attached to their molecular chain. The process of decarboxylating cannabis removes that carboxyl group from the cannabinoid molecule. This process is what effectively transforms THCA into active THC, described more below.
Some slow and natural decarboxylation occurs as fresh cannabis dries and cures after harvest. However, heat is the most quick and effective catalyst to trigger the cannabis decarb reaction. For example, decarboxylation is virtually instantaneous when cannabis is smoked or vaporized.
What Causes Decarboxylation?
The two main catalysts for decarboxylation to occur are heat and time. Drying and curing cannabis over time will cause a partial decarboxylation to occur. This is why some cannabis flowers also test for a presence of small amounts of THC along with THCA. Smoking and vaporizing will instantaneously decarboxylate cannabinoids due to the extremely high temperatures present, making them instantly available for absorption through inhalation.
While decarboxylated cannabinoids in vapor form can be easily absorbed in our lungs, edibles require these cannabinoids present in what we consume in order for our bodies to absorb them throughout digestion. Heating cannabinoids at a lower temperature over time allows us to decarboxylate the cannabinoids while preserving the integrity of the material we use so that we may infuse it into what we consume.
At What Temperature Does Decarboxylation Occur?
The THCA in cannabis begins to decarboxylate at approximately 220 degrees Fahrenheit after around 30-45 minutes of exposure. Full decarboxylation may require more time to occur. Many people choose to decarboxylate their cannabis at slightly lower temperatures for a much longer period of time in attempts to preserve terpenes. Many mono and sesquiterpenes are volatile and will evaporate at higher temperatures, leaving potentially undesirable flavors and aromas behind. The integrity of both cannabinoids and terpenoids are compromised by using temperatures that exceed 300 degrees F, which is why temperatures in the 200’s are recommended.
Heat and time can also cause other forms of cannabinoid degradation to occur. For example, CBN (cannabinol) is formed through the degradation and oxidization of THC, a process that can occur alongside decarboxylation. CBN accounts for a much more sedative and less directly psychoactive experience.
As with any other chemical process, there are certain things that need to happen in order for chemical compounds to change their structure.
Decarbing is a process that involves both temperature and time, so it’s all about balancing the two.
Luckily for us, there is a chart for that.
This is called a decarboxylation chart and it allows you to see how you can reach the desired THC by baking the buds on a specific temperature for a set period of time.
As this chart was based on a strain that can reach a maximum of 15% THC, you can see that the easiest way to reach that amount is by baking cannabis in an oven for about 7 minutes at 300°F (148°C)—or for 20 minutes at 250°F (121°C).
When decarboxylating your cannabis in an oven, it’s important to remember that the temperature dial on an oven is more of an average temperature than an exact one.
Ovens can fluctuate in temperature by 20 or more degrees, so keep an eye on your cannabis. If it turns brown too quickly or smells like it is burning, turn the oven down. An oven thermometer is a good investment if you’re going to be using your oven regularly for cannabis cooking.
- Baking tray (preferably Pyrex)
- Aluminium foil or parchment paper
Set your oven temperature to 225 degrees Fahrenheit and place the oven rack in the middle position. Ovens are hotter at the top and cooler at the bottom, placing it in the middle will ensure that you are decarboxylating at the ideal temperature.
Cut a piece of aluminium foil to the size of your baking sheet and lightly crumple it, then lay it across the baking sheet. This will minimize the direct contact of the cannabis to the baking sheet, which conducts heat better than aluminium foil and will get hotter than the air in the oven.
Lightly break up the cannabis until it is about the size of a grain of rice, too fine of a grind increases the risk of burning. Spread the cannabis across the aluminium foil, then lightly lay another piece of aluminium foil on top. Place the baking sheet in the oven and bake for 45 minutes.
After 45 minutes, remove the baking sheet from the oven and let it cool for 30 minutes at room temperature. The cannabis should look lightly toasted and golden brown.
When it is cool enough to handle, carefully put your decarboxylated cannabis into a storage container to use for future cooking.