Lay the ribs in a non-reactive pan and brush on both sides with the vinegar water mixture. Sprinkle with seasoning mix and rub with your fingertips, massaging it into the meat. Cover and refrigerate for at least 12 hours.
Start the grill, allowing it to reach a temperature of 250-degrees. Put the slabs in the grill. (If the grill is fitted with a rotisserie or carousel, attach the slabs to the apparatus.) Cook for 4 1/2 to 5 1/2 hours, turning the meat every 15 minutes (unless it is attached to a rotating apparatus). The ribs are done when the internal temperature of the meat reaches 180 degrees, when the ribs are flexible, when the meat is fork-tender, and when the ends of the bone extend about 3/8-inch below the meat.
To serve, cut the slabs into individual bones or 3, 4, or 6-rib racks. Serve immediately with or without your favorite sauce.
Recipe courtesy of John Willingham