Barbecued Baby Back Ribs

3 racks baby back ribs (pork, about 1 pound each)
1 cup ketchup
1/4 cup apple cider vinegar
1/4 cup dark brown sugar
3 T. Worcestershire sauce
1 tsp. liquid smoke
1/2 tsp. salt

Preparation -
Remove the silvery membrane from the back of the racks. Cut each rack of ribs in half. Place the ribs in a stockpot. Add water to cover the ribs. Bring the water to a boil, reduce heat, cover, and simmer for about 1 hour. While the ribs are cooking, whisk the remaining ingredients together in a saucepan. Bring to a boil over medium high heat. Reduce heat and simmer, uncovered, stirring frequently, for about 25 to 30 minutes or until the sauce begins to thicken. Turn off and set aside. Remove the cooked ribs from the pot; pat dry. Spray a grill rack with nonstick cooking spray. Place the racks, meaty side down, on the grill rack. Grill over medium hot coals for about 5 minutes per side. Brush the ribs with the sauce, turn over and grill for 2 to 3 minutes. Brush the other side with sauce, turn over and grill for 2 to 3 minutes. Serve the half racks, as is, or cut into smaller pieces. Serve with the remaining sauce on the side.