6 racks pork ribs (4 to 6 pounds baby back ribs or 6 to 8 pounds spareribs) ½ cup Coffee Spice Rub or Steven Raichlen’s Java Rub and Rib Powder (sold at barbecuebible.com), divided 2 cups wood chips (preferably hickory), soaked in cold water 1 hour, then drained, divided if using charcoal Canola oil for grill Coffee Mop Sauce (optional).
Remove the thin, papery skin from the back of each rack of ribs by pulling it off in a sheet with your fingers, using the corner of a kitchen towel to gain a secure grip, or with pliers. Rub two-thirds of the spice rub over the ribs on both sides, then transfer the ribs to a roasting pan. Cover and let marinate in the refrigerator, at least 1 hour and up to 8 hours.
Set up the grill for indirect grilling, placing a large drip pan in the center. If using a charcoal grill, preheat it to medium. If using a gas grill, place the wood chips in the smoker box and preheat to high. When smoke appears, reduce heat to medium.
When ready to cook, if using charcoal, toss half the wood chips on the coals. Oil the grill grate. Arrange the ribs on the hot grate over the drip pan. Cover the grill and smoke-cook ribs 1 hour. Uncover the grill and brush the ribs with Coffee Mop Sauce (if using). If using a charcoal grill, toss the remaining half of the wood chips on the fire. Continue cooking the ribs until tender and almost done, ½ to 1 hour longer for baby back ribs, somewhat longer for spareribs. If using charcoal, after 1 hour add 10 to 12 fresh coals per side to the grill. The ribs are done when the meat is very tender and it has shrunk back from the ends of the bones. Fifteen minutes before the end, season the ribs with the remaining rub, sprinkling it on.
Combine all ingredients in a jar, twist the lid on airtight, and shake to mix. Store away from heat and light up to 6 months. Total time is about 10 minutes. Yield is ½ cup.