INSTRUCTIONS If your cannabis is not yet decarboxylated, grind or tear it up into fairly small pieces. ... Add water to the bottom pan of your double-boiler. ... Stir in 7-10 grams of decarboxylated cannabis into the melted oil. ... Continue to heat the cannabis and oil over a low heat for 30 to 60 minutes, stirring occasionally. More items... Jan 21, 2020