Smoke Ring is important. The smoke ring develops in the first 20 minutes to an hour of the smoking process. The meat above the smoke line in the meat is easily made into bark and more flavorful. The whole mystique about the smoke ring is that the area in the 1/4-1/2 inch is a source of bark type flavor when the meat is chopped. If you cut a butt or brisket exactly on the smoke line and eat the area in the smoke ring the flavor is going to be real strong.
If you mopped, basted, or spritzed that flavor is in that area. If you chop or serve that area above the smoke line it has added a great amount of flavor. It is highly flavored and will add flavor to the whole piece.
The smoke ring is the Holy Grail of BBQ and should always be preserved and sought to create.
Tender Quick will make a great smoke ring in beef. Tender Quick will put a smoke ring all the way through the brisket because of nitrates. Nitrates will allow the smoke to penetrate all the way through the meat. That sounds good but over a 1/2 inxh on both sides of the boarder of the meat looks like you used chemicals. Its not what you want. Some cooks will cook a Brisket for 30 minutes and then wash the brisket off to get the Tender Quick off it. On a regular basis.
Nitrates at normal consumption levels doesn’t cause any physical problems so Tender Quick is okay to use on Beef. I would not use it on pork or chicken.
You can get a change in color in meat that will appear as a ring around your meat. If its not from real smoke it won’t harbor any flavor. You got to have smoke to have a real smoke ring. Texas Crutch or Boat