Step 1: The night before, unwrap the turkey, remove the giblets from the main and front cavity, and wash the bird inside and out.
Step 2: Make the brine: Place the salt, maple syrup, bourbon, and 1 quart hot water in a large deep pot and whisk until salt crystals are dissolved. Let cool to room temperature, then whisk in the cold water. Add the turkey, placing a large zip top bag filled with cold water or ice on top to keep the bird submerged. Place the turkey in the refrigerator and let marinate overnight.
Step 3: Set up your grill for smoke-roasting, placing a large foil drip pan in center.
Step 4: Drain the bird and blot dry inside and out. Tuck the wings behind the back and tie the legs together with cotton butcher’s string. Put the bird in the center of the grill grate, over the drip pan and between the mounds of coals. Toss a handful (about 3/4 cup) of wood chips on each mound of coals. Cover the grill, so that the vent holes are in the center, then adjust the vents to obtain a temperature of 325 degrees.
Step 5: Smoke-roast the turkey until cooked, 2-1/2 hours to 3 hours. Use an instant read thermometer to test for doneness—the turkey is ready when the thigh meat is 170 degrees. You’ll need to replenish the charcoal every hour—add 8 to 10 lumps of charcoal to each mound of coals and leave the grill uncovered for a few minutes to allow the charcoal to light. After 1 hour, add the remaining wood chips. There’s no need to add wood after the first hour.
Step 6: Baste the turkey with melted butter every 20 minutes. If the skin starts to brown too much, loosely tent the bird with foil. Do not wrap it tightly. On a kettle grill, you’ll probably need to shield the sides closest to the piles of coals with foil.
Step 7: Transfer the turkey to a platter and let it rest for 20 minutes before carving.