I have never cooked a bad brisket, and all my friends, local LEO Banquets, Judge's, etc use me for all their catering events.
I use a home built stick burner that is an offset with reverse flow smoke and heat.
Meat Prep: I trim out any fat that has a "hard" feel to it. Some of the fat is stiff, and some is gelatinous in the way it feels. Hard stuff needs to be taken out.
Seasonings... Plow-Boys Bovine Bold and Black pepper
injection.. Allegro's Brisket Sauce (which used to be available at my local Kroger, but I have to order it online now. I inject a bottle per large brisket 13-15lbs, and only 1/2-3/4 bottle on anything smaller. I apply a good coating of the Bovine Bold, then also a good coating of black pepper (the black pepper is on in a solid cover, and no, it will not be spicy. the beef handles the black pepper well)
Heat 315 to 335 for entire cook. Hot N Fast will never hurt a large piece of meat like brisket, butt, or shoulder.
As others have said, Cook based on internal meat temperature, not time per pound. the meat is ready when it is ready. Two pieces of meat the same exact size can be done cooking 3 hours apart. I have seen it with my own eyes.
I cook it open for the first half. this is when you are imparting the smoke flavor and getting that nice smoke ring. I wrap with heavy duty aluminum foil at 165* at the point (largest part of the brisket) At 165* I wrap with two layers of heavy duty foil (2 layers because you do not want to lose the juice that will collect as it gets done) On larger briskets, it may take 3 layers to insure you dont lose the juice.
I pull the brisket at 200* internal at the point and then put it into a cooler for a 45 min rest. After the 45 min rest, I take it out and first have a large bowl to catch the drippings that is in the foil (it will be a lot). Just stab your thermometer through the foil on the top side so the juice can not run out of the hole when you start checking for final 200* temp.
Once you catch the drippings in a bowl while un-wrapping, put the drippings bowl in the freezer while you sample and begin slicing. (this will speed up the process of separating the fat from the AusJu. When the mixture cools enough, the fat will be a white cap on top that you can easily remove with a spoon. The AusJu will be the consistency of jello or jelly and will be under the white fat cap in the bowl. Take what is left after removing the fat, and put in microwave to bring back to warm temp and pour back over the meat once sliced and in serving dish, or save for your next cook, and you can inject this in place of the "Brisket Sauce" This process will take the gritty/greasy feeling from the meat and also eliminate any possible heart burn it might would have caused. (same method for boston butts on the juice/AusJu.) The grease is what causes the heart burn that you sometimes experience in BBQ.
Slice the brisket in 1/4" slices. I always slice all of mine for catering because it yields more for serving, but by all means, separate point form flat (there is a small layer of fat between the two that you can run a long knife along and separate the two mucles that make up the full brisket), and then cube up the point (approx 1" cubes), sprinkle with more rub, then throw back on smoker for another hour or so to render out more fat, and have some "burnt ends". Hit them with a lil sweet vinegar sauce 10 mins before taking up.
Now, I do accept donations for all this knowledge that took years to develop.
