Fred, I thought the theory was that more dense smoke was produced since the fire was less efficient. This is similar to what you said about thin blue smoke. If your coal bed isn't hot enough to efficiently burn the new fuel, you get nasty by products from incomplete combustion.
Craig and Scott, you both raise some interesting points. Fred's got me in the mood for some anal extraction
This is my understanding of smoke ring and smoke flavor. They are 2 different things.
The smoke ring is a chemical reaction produced by nitrates/nitrites (and carbon monoxide in smoke). These compounds react with hemoglobin/myoglobin in the meats to produce the color you see. At a certain temperature, hemoglobin/myoglobin denature (cook) so that reaction stops. This reaction can even occur with gas if the gas is incompletely combusted.
quote:
Surface pinking, also termed �pink ring� can occur if
gas ovens or barbecue grills are used to cook meat
products. Incomplete burning of the gas or
contaminates in the gas result in the formation of
nitrogen dioxide and nitric oxide. Nitric oxide is the
active form of nitrite that yields the pink color.
Ref:
Meat Color The temperature at which myoglobin denatures is variable. Increasing the pH increases the heat stability of myoglobin. This temperature can range from 104 to 160 Fahrenheit. Starting with a cold piece of meat and raising the temperature slowly gives a more intense smoke ring because myoglobin has more time to convert before it denatures. Once it denatures, the smoke ring stops forming. As best as I can tell, this is where the idea that meat "stops taking smoke" at 140 comes from.
Ref:
Myoglobin 1 Ref:
Myoglobin 2 Starting with cold meat will increase the smoke ring. Starting with the smoke setting should, theoretically, give you a more intense smoke ring because the meat stays colder longer. I can't say I've measured the difference but I haven't noticed a big difference starting with 180 versus "smoke." I guess it also depends on what temperature your smoke setting runs.
The smoke flavor depends on the compounds in the smoke. The compounds in the smoke depend on the fuel and the efficiency of combustion. Thick, white smoke has a lot of creosote. Creosote makes the meat bitter and overwhelms other flavors. The taste we perceive is mostly due to smell so the flavors we are looking for are due to the aromatic compounds in the smoke. Higher temperatures (more efficient combustion) breakdown these compounds resulting in less "smoke flavor." What aromatic compounds you start with also plays a large part in what you end up with. Soft woods like pines are loaded with turpentine like compounds so we don't use them. Mesquite is another example of a strong flavor profile. A little goes a long way. This also explains why green wood is so strong. It has a much higher amount of aromatic compounds (as well as moisture which impedes efficient combustion) than aged wood. Over aged wood burns more efficiently (less moisture) and the flavor compounds have declined.
Because the "smoke flavor" is from the deposition of these compounds, the longer the meat cooks in the smoke, regardless of the meat temperature, more smoke flavor is deposited.
Sorry this is so long.
