I hear you. The quality of the meat is SO important when smoking a brisket. I've found it just takes time and testing to get it right. I've smoked over a dozen briskets now, and each time I learn little something new. Here are my lessons learned:
TIME: Good brisket takes flippin' forever to cook, and even longer if you want it to be as tender as possible. I normally buy a brisket that's between 12-14 pounds, and I follow the basic principle of 1 hour per pound + two hours. For example, a 14-pound brisket will take around 16 hours to cook at 220°. Keep in mind, this is just a rule of thumb...the best thing to do is place an instant thermometer into the thickest part of the brisket and check the temp regularly.
BASTE/MOP: I use a very simple solution for basting: apple juice with a splash of olive oil. I put both into a spray bottle, then shake it up each time just before spraying the brisket. I do this every hour for at least the first five hours the meat is smoking.
STALL: You will absolutely hit a stall during the cooking process. This is usually because the fat cap (which I always place up) will begin to render and melt down into the rest of the meat. This is absolutely what you want to happen, but it does cause the meat to cool down during this time. After a while, you will see the temp start to rise again, albeit slowly.
COOLER METHOD: Once the brisket reaches an internal temperature of 195°-198°, I remove it from the smoker and place it inside a large plastic oven bag (the kind people use for turkeys at Thanksgiving). I then place the wrapped brisket into the bottom of an ice chest and pile towels on top of it, basically enough to take up the free space inside the cooler. Doing this traps the heat inside. I let the brisket rest inside the cooler for 1-2 hours, which allows the juices to redistribute and the meat to continue cooking under its own heat.
So all told, a 14-pound brisket can take me 18-20 hours to get onto the table, and I plan accordingly. I usually apply the dry rub (ask me about my killer rub recipe!) ~36 hours ahead of time, then plan to wake up at an ungodly hour to get it into the smoker. This is the price you pay, but it's worth it in the end.
