Coat the meat thoroughly with the rub for as much time as possible (overnight is perfect) and refrigerate. Remove to room temp for at least an hour before smoking.
Prepare smoker – getting heat in smoking chamber to 225°F. Smoke at 215-225°F uncovered fatty side up (so it bastes itself in its own fat) on the coolest part of the smoker.
Heat up your mopping liquid in a saucepan and get something to baste/mop the brisket with. It just needs to be warm, no need to boil or even keep at a simmer.
Let the brisket smoke for an hour, then baste. Baste every hour. (see note about total cook time below). We cook a 10-lb brisket for 11-12 hours total (8-9 hrs uncovered basting every hour, and the final 3 hours wrapped in butcher paper and foil.
No matter how large your brisket is, calculate the last 30% of cooking time for the meat to be wrapped in butcher paper and then foil, or plastic wrap then foil, or even just foil if that’s all you have. This will prevent a dry brisket. When you wrap the brisket, make sure it gets one gentle mop right before removing from the grate to wrap. Wrapping also ensures a tender brisket in the end.
When it’s done, make sure it rests for at least 30 minutes. Unwrap, and slice across the grain, or chop for chopped brisket sandwiches