With electric smokers, the chemical reaction that causes a smoke ring is much less since the wood smoke density is much less. The previous poster is also correct about the presence of nitrates and nitrites (which also occur in heavy wood smoke and charcoal smoke). I don't use them if I can avoid it. I think the smoke ring is a big myth of BBQ. Sort of a religious talisman that doesn't really mean anything. Like the previous poster, I can't taste it, so why do I care about it? Search this site for more opinions. You'll find that KCBS does not allow smoke ring as a criterion for competition judging.