Instructions

for the sauce

Whisk 1 cup ketchup, ¼ cup water, 1 tablespoon pepper, 1 tablespoon onion powder, 1 tablespoon Worcestershire sauce, 1 tablespoon light corn syrup, 1 tablespoon granulated garlic, 2 teaspoons celery seeds, and ½ teaspoon liquid smoke together in medium bowl to combine; set aside.

for the ribs

Combine 5 tablespoons packed light brown sugar, 1 teaspoon salt, and ½ teaspoon pepper in bowl. Pat 5-6 pounds baby back ribs, trimmed and membrane removed, dry with paper towels and rub with sugar mixture; set aside. Using large piece of heavy-duty aluminum foil, wrap 1 cup cornmeal in foil packet and cut several vent holes in top.
Open bottom vents of charcoal grill halfway. Place 13 by 9-inch disposable aluminum roasting pan on 1 side of grill and fill pan with 2 quarts water. Arrange 3 quarts unlit charcoal briquettes on opposite side of grill. Place 6 corncobs, kernels removed, on top of unlit briquettes. Light large chimney starter filled halfway with charcoal briquettes (3 quarts). When top coals are covered with ash, pour over cobs and unlit coals. Place cornmeal packet on coals. Set cooking grate in place, cover, and open lid vent halfway. Heat grill until hot and cornmeal is smoking, about 5 minutes.
Clean and oil cooking grate. Place ribs, meat side up, on cool part of grill opposite coals. Cover, positioning lid vent over ribs, and cook until ribs are deep red and tender, 3½ to 4 hours, rotating ribs and switching positions every hour. (Do not flip ribs.) During last 30 minutes of cooking, baste ribs every 10 minutes, rotating and switching ribs each time. Transfer ribs to carving board, tent loosely with foil, and let rest for 15 to 20 minutes. Cut ribs in between bones and serve, passing remaining sauce separately.