Here is my reaction to that article. I'll preface my interjections by putting Monty before my comments.
AUTHOR: When a smoke ring develops in barbecue meats it is not because smoke has penetrated and colored the muscle, but rather because gases in the smoke interact with the pigment myoglobin.
MONTY: My point exactly. It is not that smoke penetrates the meat thus causing the smoke ring. It is the gasses in the smoke that cause the smoke ring. However, smoke is still necessary as it transports the necessary agent to the meat. Let's continue...
AUTHOR (EMPHASIS CAPPY):
Two phenomenon provide evidence that it is not the smoke itself that causes the smoke ring. First, it is possible to have a smoke ring develop in a product that has not been smoked and second, it is also possible to heavily smoke a product without smoke ring development.
MONTY: What does that mean? Can I cook a brisket in a crockpot and get a smoke ring? No. How about a convection oven? No. Not unless nitrogen can be produced in those environments. However, our good author moves beyond theory to practice - as I suggest we do, by writing the following:
AUTHOR: Most barbecuers use either wood chips or logs to generate smoke when cooking. Wood contains large amounts of nitrogen (N). During burning the nitrogen in the logs combines with oxygen (O) in the air to form nitrogen dioxide (NO2). Nitrogen dioxide is highly water-soluble. The pink ring is created when NO2 is absorbed into the moist meat surface and reacts to form nitrous acid. The nitrous acid then diffuses inward creating a pink ring via the classic meat curing reaction of sodium nitrite. The end result is a "smoke ring" that has the pink color of cured meat. Smoke ring also frequently develops in smokehouses and cookers that are gas-fired because NO2 is a combustion by-product when natural gas or propane is burned.
MONTY: Catch that? The nitrogen from the wood combines with the oxygen and forms NO2. This is absorbed into the meat and hey presto, a smoke ring.
Now check this out. He actually tells us how to get a smoke ring - by SMOKING the meat.
He says it right here -
AUTHOR: Let’s review the conditions that would help to contribute to the development of a smoke ring. Slow cooking and smoking over several hours. This allows time for the NO2 to be absorbed into and interact with the meat pigment.
MONTY: some text has been cut but he continues...
AUTHOR: Generate smoke from the burning of wood chips or wood logs. Since NO2 is a by-product of incomplete combustion, green wood or wetted wood seems to enhance smoke ring development. Burning green wood or wetted wood also helps to increase the humidity level inside the cooker.
A high temperature flame is needed to create NO2 from nitrogen and oxygen. A smoldering fire without a flame does not produce as much NO2. Consequently, a cooker that uses indirect heat generated from the burning of wood typically will develop a pronounced smoke ring. Have fun cooking. A nice smoke ring can sure make a piece of barbecued meat look attractive.
MONTY: In theory one does not need smoke so long as the chemical reactions take place. But outside a chemestry lab one needs the presence of smoke for a smoke ring.
IMHO smoke is the cause of a smoke ring - even if it is not theoretically the only way to get a smoke ring.
Certainly the claim that smoke has nothing to do with a smoke ring is not supported by this man's article.