After five to six hours of cooking, wrap the brisket in double sheets of heavy-duty aluminum foil, add 1/2 cup of the mop (instructions below), tightly seal and return to grill for another hour or so, keeping the temperature at 225°F. (Paul Kirk, Ph.B., the Kansas City “Baron of Barbecue” and author of numerous barbecue books, calls this method the “Texas crutch” and says it steams the brisket. He doesn’t recommend foiling.)
When the brisket reaches an internal temperature of 180°F, remove the foil and place the brisket back on the grill to finish cooking to an internal temperature of 185°F. About 30 minutes before serving paint the brisket with finishing sauce, if desired.