Newbie to smoking here, I've seen mention on other threads about a water pan for smoking brisket.
I had thought all the brisket needed was a good rub and a drip pan, then smoke for hours. I'm assuming the water pan is to add moisture - is this the recommended method?
My understanding is that a water pan has two potential benefits. First, like you said, it increases the moisture level in the smoker. Since so much moisture if being generated by the fat in the meat, I doubt this makes a big difference.
The other benefit is that it helps regulate heat. The water will heat up so that when you open the smoker it doesn't lose as much heat and take as long to heat back up again. Also, I think it would help balance out any hot or cold spots in the smoker.
Zero to do with adding moisture (that's the theory, anyhow, that it adds moisture...). It does NOT add moisture according to "some" who have soldiers in that battle, re: in the argument.
The reason they say it does NOT add moisture is because for the water to reach a purely vapor state (which then has to have this steam penetrate the meat... well, more than penetrate, it has to want to / be induced to enter & @ the same time the meat has to "invite" of sorts the moisture through various points of entry.
Think of it like this; if you do a rub, you are suggested to massage the spices into the meat, thereby forcing it (however lightly) into the grain. If you do a liquid soak (marinade) then you're hoping there will be some kind of a sponge effect by the meat & it pulls in the liquified seasoning.
One thing to consider about meat in a heated environment - it contracts. Ever started with a 16" long piece of brisket that constricts down to 12"?
Another reason for having a water pan (in "some" types of smokers is to diffuse the heat a bit so you get more of the indirect heating. It's easier & less expensive to do a water pan than to build solid metal baffles.
Additionally, in something like a bullet smoker & some indirect / offset smokers, a water pan is a place to collect grease or drippings so that you don'g get a grease fire or have nasties to collect up from the bottom of the smoke chamber.
I have done identical smokes with straight water in the pan filled to a specific level & then done the exact same size with the water pan filled with beer... same time, same weight of brisket (within 1/2 lb).
ZERO difference in taste.
If you were to go to any large scale BBQ cookoff, ask to check out the rigs. You won't see any water pans anywhere.
I've found a water pan helps me in keeping the temp a little more constant in my pretty cheap smoker setup.
The biggest thing to remember about smoking & BBQ is to experiment (you'll screw up more than a few times) and do what works for you, your rig, your eating audience, your geographical location, your food preferences, etc. And, lastly, enjoy the experience!