With barbecue, a smoke ring is a pink coloration just under the crust or skin of the meat, ranging in depth from a millimeter (about .04 inch) to several centimeters (an inch or more). But as Duppie asked on Chowhound, does a smoke ring always indicate barbecue skill, or can it be faked with chemicals?
The smoke ring can be chemically produced, charles_sills says. And even if it's not, a smoke ring isn't necessarily an indication of the barbecue-maker's chops: Meat left a long time in the smoker can have a beautiful ring, even though the texture is dry as a bone. Anyway, scubadoo97 says, a smoke ring is merely a chemical reaction between the nitrogen dioxide in the wood smoke and the myoglobin in meat (you can't get a smoke ring from an electric smoker).
Even if smoke rings are not 100 percent reliable as indicators of quality, cowboyardee thinks they do generally indicate a good cooking process that is rightly associated with delicious taste and texture. A smoke ring is similar to other fallible-but-informative visual cues in food, like the oily slick on top of coffee prepared in certain ways, the leopard spots on the crusts of traditionally made Neapolitan pizzas, or even grill marks. These may not add flavor themselves, cowboyardee says, but they are an appetizing visual indicator that food was prepared skillfully.