Rub the five-spice powder and pepper evenly over ribs. Transfer to an extra large resealable bag (alternatively, the rib rack can be cut to fit in a gallon-sized bag).
Combine the remaining ingredients in a bowl. Add to the pork in the bag. Seal and transfer to the refrigerator. Marinate overnight.
Heat grill to 250-300°F. Line a rimmed baking sheet with foil, and set a wire rack in it. Remove the ribs from the bag, draining excess marinade off into the bag (reserve the marinade), and lay the ribs on the rack. Cover with aluminum foil and roast on the grill by indirect heat for 2 hours.
Meanwhile, simmer the reserved marinade in a small saucepan on med-low heat for 20 minutes, whisking regularly. Stain through a fine-holed strainer, pressing the congealed bits to squeeze out the juice (this sounds terrible, sorry).
Remove the foil from the ribs and brush on the marinade. Increase heat to med-high (400-450°F), place ribs back on the grill and continue to roast until charred and glazed, ~20 minutes longer, uncovered to prevent scorching (see Notes), turning and brushing with marinade every 5 minutes. Remove from the heat and let rest 5 minutes. Cut into individual ribs and serve. Yields: 4-6 servings.