I think I just realized that one shouldn't heat the weed for too long, even though it's at a low temperature. I let some bud heat at around 170 or so for a very long time and it ended up having no smell left over and the bud looked a little brownish.

My guess is, to not cook it so much that there is no smell left. Or just heat it up and take note of the smell.. when the smell gets duller you have gone too long. It might do something to you but it's not the same I think.

So.. I'm guessing don't do it more than the 40 minutes I'd say. I would even take it out sooner.