Selecting a Brisket: The first step is to select a good brisket. A good brisket has about 1 to 2 inches of fat evenly distributed over the top. This is called the fat cap. A good brisket also has good marbling throughout the meat. This means that there are nice thin ribbons of fat through the meat. This fat is what keeps the brisket moist while it smoked. Of course it can be hard to tell; especially if you are buying briskets that have been vacuum packed but try to at least look all over the brisket to get an idea of the fat distribution. As with anything the more you do the better you'll get. Also, look for a brisket that is about 6 to 10 pounds in weight. This is a good size for brisket.
Preparing a Brisket: Next you'll want to prep your brisket for smoking. You want to leave the fat cap intact but you don't need more than about 1 to 1 1/2 inches of fat in the cap. Any excess can be trimmed off before you smoke. Once you have your brisket the way you want it you should marinate the brisket overnight to add moisture and flavor to the meat. A good brisket marinade will contain something acidic to help penetrate the meat, like come kind of vinegar or citrus juice. Add seasonings to the marinade to add the flavor. A large resealable bag works best for marinating a brisket. Put the brisket in the bag, pour in the marinade, force out as much air as possible and seal.
Rubbing a Brisket: Once the brisket is marinated remove it from the bag and let it drain. You will want the surface to be relatively dry so you can add a dry rub. A good rub will add flavor to the brisket but not over power it. Many cooks use paprika because of its mild flavor and because it adds a nice color to the brisket. To help get the flavor under the fat cap you can cut small holes through the fat cap down to the meat and pour the rub inside. As the fat melts it will carry this flavor into the meat. Rubbing the fat cap down with seasonings won’t do you much good so don’t waste your time.
Smoking a Brisket: The most important thing about smoking your brisket is maintaining a good temperature. It really doesn't matter as much what kind of smoker you use, just as long as it can hold a temperature between 200 and 225 degrees F. for 15 to 20 hours. This will require that you are available to check on the smoker frequently during the cooking time.
Place the brisket, fat side up (read: Brisket - Which Side Up?) in the preheated smoker. You will want to rotate your brisket at least once during cooking to even out the exposure to the heat. Typically it takes about 1 1/2 hours per pound to smoke a brisket. The time is dependent on you. One method is to smoke for one hour per pound, wrap the brisket in heavy foil and place it in a cooler for several more hours. You use the cooler to hold in the heat so that the brisket continues to cook and tenderize from its own heat. If you choose to smoke your brisket longer it may dry out. Personally I smoke my briskets for closer to two hours per pound and baste it after ten hours. I haven't had a brisket dry out on my yet, but I know several people who have.
You should use some wood to make smoke while cooking your brisket. Smoke added at the beginning of the smoking time will add a lot more flavor that smoked added later. For a brisket you want to stay away from bitter woods like mesquite because the flavor will become too strong. A mild fruit wood like apple or cherry or a mild wood like pecan or oak is best. If you use charcoal for your fire, pick a good plain charcoal without additives. Lump charcoal works best because it is much more like really wood.
Technically your brisket is done when the internal temperature reaches around 160 degrees F. However for a brisket to be truly tender it will need to continue to smoke for longer (target temperature around 185 degrees F.). The cooler method works by keeping the brisket at this temperature for several hours allowing the fat to continue to melt and add moisture to the meat. If you leave your brisket on your smoker after it has reached the ideal temperature you will want your smoker temperature to be around 200 degrees F. to help prevent the meat from drying out.