Combine all marinade ingredients in a medium-sized mixing bowl. Whisk gently to combine.
Transfer the brisket to a pot that can comfortably accommodate the meat without leaving too much extra room. Cover with the marinade and top with plastic wrap placed directly against the surface of the marinade. Refrigerate for 16 hours until well marinated.
Preheat and set grill to 220° F for indirect cooking.
Remove brisket from marinade and shake off any excess. Place the brisket over a drip tray on the unlit side of the grill, fat-side up.
Add wood chips to smoker box and place on direct-heat side.
Cook at 220° F until preferred doneness is achieved, approximately six to eight hours. See internal temperatures below.
When the meat is very tender, remove from heat and wrap in cling wrap and then a layer of foil. The steam will help continue breaking down the brisket.
Rest meat for two hours: this is crucial for a moist, mouth-watering brisket.
Slice thinly across the grain to serve.
Medium-rare 63° C (145° F) Medium 71° C (160° F) Well done 77° C (170° F)