Smoke ring

A smoke ring is the pink band, usually a few millimeters deep, that shows up just under the surface when a properly smoked piece of meat is sliced open. It forms when nitrogen dioxide from wood smoke and combustion dissolves into the moist surface of the meat and reacts with myoglobin, the pigment in muscle that also gives raw meat its red color, fixing it in a stable pink state that does not fade with further cooking.

Despite how it looks, a smoke ring has nothing to do with whether the meat is safe to eat or fully cooked. Fully cooked, safely rested smoked meat can and often does have a smoke ring, while meat cooked well past done can still show one if the right smoke chemistry was present early in the cook, since the ring forms mainly in the first hour or so before the surface temperature gets too high for the reaction.

A stronger smoke ring generally comes from a longer, cooler start to a cook, more moisture on the meat's surface early on, and burning wood or charcoal that produces steady, clean smoke. It is mostly cosmetic. Competition cooks chase it because judges expect to see it, but for home cooking it is a nice sign of a good low and slow session rather than a mark of quality on its own.