I get propane and smoke tubes both produce NO2 and smoke particles, never imagined to get such a nice smoke ring with a 4 hour cook, no wrap. Also got similar ring with a 6 hour pork butt smoke (and another 4 hours oven wrapped) with the same setup. Both on an old Weber Espirit grill at 275F and 1 to 2 smoke tubes with hickory and/or mesquite pellets and chips mixed. Anyone else experience rings with propane/tubes?

PS: Run does not have nitrates/celery salt/etc.