Put a butt on tonight. I had a 3 oz or so piece of hickory wrapped in foil with hole punched in it, and another a little smaller laying in the wood tray. The tray is lined with about 5 layers of heavy foil. In the past, I've not used that much wood. After it started smoking, I checked on it, and the smoke was pretty heavy. I decided I needed to back off on the wood. As I started outside, it belched real big. Why do they belch like that? I turned it off, opened the door, and let the thick smoke clear out. I removed the foiled piece of wood, and started it back up. Thin white smoke now. Should last about 2.5-3 hours, then I'll add more wood. I never get over 3 hours of smoke from a 3-4 oz piece of wood.