Make sure to set the grill or smoker to the correct temperature before adding the brisket. If the temperature is too high, the meat will dry out, especially if it's left in there for too long. One issue might be with the smoker itself—or more specifically, the way it's configured.
How do you keep brisket from drying out?
To keep your brisket moist and juicy, put a water pan in your smoker and spray it with water, apple cider vinegar, or apple juice every 30 to 60 minutes. Using the Texas crutch is another way to lock in moisture. This technique involves wrapping the brisket with butcher paper or foil when it reaches about 160 F.
At what temp does brisket dry out?
If you cook brisket at high temperatures above the 250°F range, you risk drying it out. High heat will cause the brisket to lose moisture and contribute to the dryness. Brisket needs to be cooked low-and-slow at about 225°F (107°C).