Take a pork butt right out of the fridge & put it on the smoker with no rub - you'll get a very pronounced smoke ring.
CBJ # 22569
KCBS BoD Judges' Advocate
Possibly the only judge ever to get an award from a bunch of cooks
UDS 075 UCB WSM and a bunch of other stuff.
The above post is only my opinion - mine & mine alone.