Did 3 racks of spares last weekend for my oldest son's birthday (which is this weekend, but they're getting drunk this weekend, lol..). The ribs came out great, got a few pics of them after slicing them to demonstrate the smoke ring (after cutting off the briskets):
But, what is a "smoke ring"?
Pink is beautiful
Many smoked meats develop a smoke ring, a bright pink color just under the surface. Some people think the pink color means the meat is raw, but nothing could be further from the truth. There is a picture of a pork rib with a smoke ring at the top of this page.
Nitrogen dioxide (NO2) is among the compounds formed in the high heat combustion of wood, charcoal, and even propane. As these compounds land on the surface of meat, especially cool moist meat from the fridge, some, including nitrogen dioxide, are moved deeper into the meat as cells lower in the smoke compounds pull them in with a diffusion and absorption process. The cells are simply seeking equilibrium. The process is the same as when someone lights a cigar in a room. All the smoke starts out near the cigar, but eventually it spreads throughout the room as it achieves equilibrium. After a while it penetrates clothes, furniture, and even food. Because it is water soluble, cigar smoke will get into wet things first, like your wife's eyes. Before long you and your cigar will be seeking equilibrium in the garage.
The smoke ring in meat is caused by four things:
1) low temperature cooking,
2) combustion of the wood at high temperatures to form nitrogen dioxide,
3) nitrogen dioxide, and
4) moisture on the surface of the meat to help move the water soluble nitrogen dioxide into the meat.
When these conditions are met, nitrogen dioxide in wood smoke reacts with the pigment myoglobin in meat to form nitrites and nitrates. These are the same compounds added to hot dogs and other cured meats to preserve them and they also give them their pink color.
When smoke roasting, the moist meat absorbs smoke. Less smoke is absorbed as the cooking continues because the surface of the meat begins to seal and becomes saturated with smoke. For this reason putting a pan of water in a smoker helps create a smoke ring. In fact some smokers, called water smokers, have water pans built in.
Most of the smoke flavoring occurs in the first hour or two of cooking so adding wood to the fire late in the cook doesn't create as much flavor. It also allows moisture to escape. It's better to just leave the door closed.
So, by smoking we are naturally preserving the meat to some extent by the action of naturally curing the meat with nitrites and nitrates. Then, when you intentionally cure the meat with nitrite all the way through into a cured and smoked product you're just finishing the job that nature and science started, lol!