Decarboxylation (Decarb)
Definition: Decarboxylation is the heat-driven chemical reaction that converts acidic cannabinoids in raw cannabis, mainly THCA and CBDA, into their neutral forms, THC and CBD. The reaction releases carbon dioxide and happens almost instantly when flower is smoked or vaporized, but must be done as a separate step before making edibles or infusions.
How Decarboxylation (Decarb) works
Living and freshly dried cannabis produces cannabinoids in acid form. THCA, the dominant one in most modern strains, is not intoxicating on its own. Heat removes a carboxyl group from the molecule, releasing it as CO2 and leaving THC behind.
Why the weight drops
Because part of the molecule leaves as gas, converting THCA to THC loses about 12% of its mass. That’s where the 0.877 factor in the total THC formula comes from: each unit of THCA yields at most 0.877 units of THC.
Oven decarb basics
- Break flower into small pieces and spread them on a baking sheet lined with parchment.
- Bake at roughly 230 to 250°F (110 to 120°C) for 30 to 45 minutes.
- Cover the tray or use an oven bag to reduce odor and trap some aroma compounds.
- Use an oven thermometer; many home ovens swing 20°F or more from the dial setting.
Common mistakes
- Too hot or too long: THC begins breaking down into CBN, and many aromatic terpenes evaporate.
- Too cool or too short: conversion is incomplete.
- Skipping it entirely: raw flower stirred into butter or oil at low temperature stays mostly THCA.
Slow decarb in storage
Some conversion happens naturally during drying, curing, and long storage, especially with warmth and light. It’s slow and uneven, which is why intentional heating is used for edibles. The same process applies to CBD strains, where CBDA converts to CBD.