Here’s a fun fact to bring to your next get-together: if you ate a fresh cannabis bud straight off the plant, you’d feel very little. Not because it’s weak, but because it hasn’t been switched on yet. The switch is heat, and the process has a mouthful of a name: decarboxylation.
The on switch
A living cannabis plant doesn’t really make THC. It makes THCA, an acid version of it that doesn’t get you high. Same goes for CBD, which starts life as CBDA.
When you add heat, THCA sheds a small piece of itself (a carboxyl group, which floats off as a puff of carbon dioxide) and becomes THC. That’s it. One tiny molecular change, one very big difference.
Where it happens in real life
- Lighting up or vaping: the heat flips the switch instantly, right as you inhale.
- Edibles, drinks and oils: the producer has already heated the cannabis during production, so they’re ready to go.
- Your stash, slowly: a little decarboxylation happens naturally over time. Leave flower for long enough and some of the THC also breaks down into CBN.
This is why the label has two THC numbers
“THC” is what’s already switched on. “Total THC” estimates what you’ll get once heat does its thing. If you’re comparing flower, Total THC is the one that counts.
Heat giveth, heat taketh away
Terpenes are delicate and start to evaporate at lower temperatures than THC needs. Too much heat and you lose flavour. That’s why many vaporizers let you set the temperature: lower settings for flavour, higher for fuller clouds. It’s also why your flower should never live on a sunny windowsill.
Try this
If you have a temperature-controlled vaporizer, start your next session at the low end and step it up gradually. Notice how the flavour changes as you go. It’s the easiest way to taste terpenes and decarboxylation in action.