Soak the wood chips in water for at least 30 minutes.
Prepare the grill for direct cooking over medium heat (350° to 450°F).
In a small bowl mix the rub ingredients.
Using a dull dinner knife, slide the tip under the membrane covering the back of each rack of ribs. Lift and loosen the membrane until it breaks, then grab a corner of it with a paper towel and pull it off.
Related Grill Skills
Removing the Membrane from Baby Back Ribs
Season each rack evenly with the rub. Using four 18-by-24-inch sheets of heavy-duty aluminum foil, double wrap each rack in its own packet.
Brush the cooking grates clean. Place the ribs on the grill over direct medium heat , close the lid, and cook for 1 hour, occasionally turning the packets over for even cooking, making sure not to pierce the foil.
Remove the packets from the grill and let rest for about 10 minutes. Carefully open the foil packets, remove the ribs, and discard the rendered fat and foil.
Drain and add the wood chips to the charcoal or to the smoker box of a gas grill, following manufacturer’s instructions, and close the lid. When the wood begins to smoke, return the racks to the grill, bone side down. Grill over direct medium heat, with the lid closed, until they are sizzling and lightly charred, 10 to 12 minutes, turning and basting once or twice with the sauce. Remove from the grill and let rest for about 5 minutes. Cut into individual ribs and serve warm with any remaining sauce.