Pork ribs include a variety of of cuts, but usually are either baby back ribs or pork spare ribs. The method for cooking either cut on a grill is not very different except for the time to cook them -- spare ribs tend to need more time to fully cook and become tender because of their higher fat content. To get well-cooked pork ribs, the name of the game is low and slow -- tender, juicy ribs require low-heat indirect cooking and moderately long cooking times. Traditionally, barbecue pork ribs are made in smokers or barbeque pits, but you can use your home propane grill and get satisfactory results.
Marinate and Flavor
Start the ribs by setting them in a pan large enough to fit them and cover with an acidic marinade. For traditional-style barbecue, use apple cider or apple cider vinegar mixed with a small amount of lemon. Refrigerate and allow the ribs to marinate for 4 to 6 hours.
Remove the ribs from the marinade and blot dry with paper towels.
Coat the ribs with either a store-bought barbecue dry rub or a rub of your own creation. Dry rib rubs typically include some combination of brown sugar, paprika, salt, pepper, cayenne pepper and garlic; add your favorite herbs and spices to the basics for your own signature mix.
Transfer dry-rubbed ribs to a platter, cover and refrigerate for 1 to 2 hours.
Set Up the Grill
Set up your grill for indirect cooking and smoking by first placing water-soaked wood chips into a smoker box -- if you have one -- or a pouch made of aluminum foil poked with holes with a metal or wood skewer.
Place the wood-chip-filled smoker box or aluminum foil pouch on the cooking surface of the grill, directly over an outside burner. Do not place the chips over a middle burner.
Preheat the grill on high until the wood chips begin to smoke, then completely turn off the heat on the half of the grill that does not have the smoking wood chips. Turn the side with the smoking wood chips down to medium heat.
Cook the Ribs
Place the racks of ribs, meat side down, onto the cool side of the grill and lightly brush with a small amount of apple cider vinegar.
Close the grill and cook for about 30 minutes, then open the grill and brush the ribs with more apple cider vinegar, flip the ribs, and rotate them -- move the ribs that were further from the heat closer and those closer to the heat further away. This allow each of your rib racks to finish at roughly the same time and receive similar amounts of heat over the length of cooking.
Repeat the brushing, turning and rotating process every 30 minutes until the ribs are fully cooked -- typically this takes from 2 to 3 hours. The ribs are fully cooked when they can be easily pulled apart with your fingers, but insert a meat thermometer to test for doneness; pork should have a minimum internal temperature of 145 degrees Fahrenheit, according to FoodSafety.gov.
Remove the cooked ribs from the grill onto a large platter. Tent the platter with aluminum foil and allow the ribs to rest for at least 10 minutes.
Serve the ribs with your choice of barbecue sauce on the side or, if you prefer, coat with sauce before serving.