Hi all - in my experience so far (2 weeks) using my 22" WSM I expected that when whatever I had cooking was finished, I could shut down the bottom/top vents and the fire would extinguish so that I could save some of the coals. This hasn't been the case. It keeps going and going and ... which, if I wanted to do a 12-hour slow-smoke (brisket on Friday!) would be great, but I'm not.
If closing all the vents doesn't do it, what does, if anything?