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What causes a smoke ring?


I found a great article that explains the science behind the smoke ring, so I though I would share it with you. The photo is a brisket I cooked last summer. Now that’s a smoke ring!

What is the Smoke Ring and Why Is It There!
How to Get That Coveted Pink Ring With Your Cooking

by Joe Cordray

Slow cooked barbecue meats often exhibit a pink ring around the outside edge of the product.
This pink ring may range from 1/8 inch to 1/2 inch thick. In beef the ring is a reddish-pink and in
pork, chicken and turkey it is bright pink. This pink ring is often referred to as a “smoke ring”
and is considered a prized attribute in many barbecue meats, especially barbecue beef briskets.
Barbecue connoiseurs feel the presence of a smoke ring indicates the item was slow smoked for a
long period of time. Occasionally consumers have mistakenly felt that the pink color of the
smoke ring meant the meat was undercooked. To understand smoke ring formation you must first
understand muscle pigment.
Myoglobin is the pigment that gives muscle its color. Beef muscle has more pigment than pork
muscle thus beef has a darker color than pork. Chicken thighs have a darker color than chicken
breast thus chicken thigh muscle has more muscle pigment (myoglobin) than chicken breast
tissue. A greater myoglobin concentration yields a more intense color. When you first cut into a
muscle you expose the muscle pigment in its native state, myoglobin. In the case of beef,
myoglobin has a purplish-red color. After the myoglobin has been exposed to oxygen for a short
time, it becomes oxygenated and oxymyoglobin is formed. Oxymyoglobin is the color we
associate with fresh meat. The optimum fresh meat color in beef is bright cherry red and in pork
bright grayish pink. If a cut of meat is held under refrigeration for several days, the myoglobin
on the surface becomes oxidized. When oxymyoglobin is oxidized it becomes metmyoglobin.
Metmyoglobin has a brown color and is associated with a piece of meat that has been cut for
several days. When we produce cured products we also alter the state of the pigment myoglobin.
Cured products are defined as products to which we add sodium nitrate and/or sodium nitrite
during processing. Examples of cured products are ham, bacon, bologna and hotdogs. All of
these products have a pink color, which is typical of cured products. When sodium nitrite is
combined with meat the pigment myoglobin is converted to nitric oxide myoglobin which is a
very dark red color. This state of the pigment myoglobin is not very stable. Upon heating, nitric
oxide myoglobin is converted to nitrosylhemochrome, which is the typical pink color of cured
meats.
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.
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.
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.

About the Author:
Joe Cordray is the Meat Extension Specialist at Iowa State University’s nationally renowned Meat Lab, located in

Ames, IA. He has been writing for The BBQer since Fall of 2001

3 Responses to “What causes a smoke ring?”

  • [...] recently discovered it and really enjoy his photos and recipes. Check out this post about What causes a smoke ring. This entry was posted in Grilling. Bookmark the permalink. ← Fresh Made [...]

  • Duckster:

    For a competition smoker who can’t use any propane and/or gas – do you have any other tip to use to get a decent and deep smoke ring about every time. Love the website, have learned a lot already…

  • Mister Bob:

    The more fuel your cooker burns, the deeper the smoke ring it will produce. That’s because more combustion means more nitrous oxide produced. The nitrous oxide combines with another oxygen molecule in the presence of heat and forms nitrous dioxide. This meets the water on the surface of the meat and forms nitric acid, which reacts with the myoglobin to form the smoke ring. More combustion means more nitrous dioxide passing over the surface of the meat through convection. More combustion, more smoke ring. You could also fake it by applying Morton’s Tenderquick to the surface of the meat, which does the same thing, but most people would consider that cheating.