24 hours ahead, combine the brine ingredients in a large bowl. Place the brisket in an extra large ziplock and pour the brine over it. Seal well and place in a shallow pan in the refrigerator overnight.
The next day, prepare the Keg for direct grilling at 225°F and add the wood chips. Drain the brisket and pat it with the rub. Place the brisket on the Keg and mop every 45 minutes for 3 1/2 hours. Wrap the brisket in foil and continue to cook at a low temperature for another 2 hours.
Cook to internal (endpoint) temperature of 180°F–185°F
Let the brisket stand at room temperature for 20 minutes, then slice thinly against the grain. Serve with your favourite mustard, pickles.