Started a full packer late Friday night. I had stabilized dome temp at 225 before putting in (about 45 minutes), then got it back to 225. Waited another 45 minutes before going to bed. When I awoke, the temp was pushing 400 and the flat was like shoe leather (the point wasn't too bad though).
I've done several long cooks, this was the first to go awry. Was I just lucky in the past? What is a reasonable time to wait to confirm it's stable?