Q: Dr. BBQ:
My source tells me that when meat has been smoking approximately four to six hours and has reached an internal temperature of 140 degrees, it has most likely consumed the desired volume of uptake smoke it needs. The rest of the time spent throwing wood on the fire is for doneness. Correct me if I am wrong. Thanks!
This is a common misunderstanding. Not sure who your source is, but they have confused the process that creates the coloring we call smoke ring, with the flavoring of the smoke. The coloring will cease at about 140, but the smoke flavor will continue as long as the meat is exposed to the smoke.