Gray explains the science thusly: "Raw cannabis contains a lot of THCA, which is nonreactive. When you smoke cannabis, it heats up to a certain temperature and loses a CO2 molecule and becomes THC, which has the psychoactive benefits that many users are looking for." Simply simmering cannabis in butter, or oil, isn't always enough to fully convert all of the THCA into THC, he continues. And so, the result is less than optimal: "You're going to make a very dull cannabutter," he says.
The best method, Gray says, involves some added prep work. "So, instead of just, say, sticking your cannabis in butter or sticking it in oil, you should first grind it onto a baking sheet, stick it in your oven at 310-degrees Fahrenheit for about 10 to 18 minutes. That allows it to become psychoactive and it's ready to cook with."