I did an overnight cook last night. I did 4 butts on the 18.5". The two buts on the bottom shelf had bark that was too hard. It was difficult to eat and I certainly wouldn't serve that part. I hated it because I wasted so much of my favorite part. Did I cook it too long? My temp gauge was never above 225 (I use the on board temp gauage). I was wondering if its cold outside if the on board temp gauge is affected? Thoughts? Thanks in advance.