>And according to a forthcoming book from the CIA, contrary to what KYH said upthread, any smoke does add flavor, provided the particles of smoke can cling to the surface of the food.<
That's not quite what I said, Suzanne. Of course the smoke adds flavor, otherwise why bother?
What I said was that, with the exception of a very few aromatic woods, that the smoke flavor imparted is indistiguishable, one wood to another, if everything else is help constant.
I've been playing with smoke---both for smoke cooking and smoke curing--- for about 40 years and stand by my statement. I've met many people, professionals and just plain folks, who are very contentious about the choice of wood and how it flavors the food. In each case where I could convince them to take a blind taste test they could not tell which sample was cooked by which wood, because they tasted the same.
In short, as so often happens with culinary matters, conventional wisdom and in-the-mouth testing yield totally different conclusions.
The problem is, often, that different dishes are cooked using different woods. For instance, a lightly seasoned fish might be smoked with apple wood. Then a heavily spice-rubbed brisket is smoked using hickory. And the conclusion is that the radically different tastes are from the wood. But it's just not so. Or, in a similar vein, two dishes might be prepped the same, but one dish is lightly smoked, the other deep smoked. And, again, the type of wood is said to be the cause.
Another aspect is the age of the wood. Relatively green mesquite, alder, and the stems from herbacious herbs will add their flavors to the food as their aromatic oils volitize then recondense on the food. But even those woods, when well aged, contribute little if anything because their oils already have evaporated.
> Which is why the surface of the food should be dry, preferable with a pellicle (a skin formed by the drying of the brine or marinade).<
Absolutely correct. Without the pellicle you're pretty much spinning your wheels. Although there's more involved in the formation of a pellicle then just drying the brine or marinade.
It's also why dry rubs are so preferred over brines, nowadays. It takes considerably less time for the pellicle to form with a dry rub. If you're interested in why, I'll be happy to explain.
Still another aspect, btw, is the time-shedule of the smoking. Much has been made about how the food can only absorb X hours of smoke. Just this week one of the celebrity chefs made a big deal about there being no use smoking for more than two hours because that's all the smoke the meat he was making (a pork shoulder, for pulled pork) could absorb.
In one sense that's correct. At the start, two hours of smoking is about max (it varies, naturally, based on factors like the type of protein, seasoning used, strength of the pellicle, etc.). However, if you then let the food rest with no smoke for a half hour, then start smoking again, it will happily absorb more. The more you alternate smoke/no smoke on a 30 minute alternation the smokier the food will taste, and the deeper the smoke ring will extend into the food.
To be sure, scheduling of smoke is more a concern with smoke-curing than with smoke cooking. But it's another instance of "experts" making categorical statements that are not borne out by the facts.