Baby Back vs. St. Louis Ribs: Differences Between the Pork Cuts

Baby back ribs, also known as loin back ribs, are slightly curved bones from the top of the pig’s rib cage below the loin muscle. These pork ribs, located near the backbone, are wider on one side and smaller than spareribs, earning them the “baby back” name.

Their tender, juicy meat comes on a rack of ten to thirteen ribs, which grill masters often flavor with a sweet or smoky barbecue spice rub. The best way to prepare baby back ribs is through indirect cooking since the curved bones make it challenging to cook evenly with direct heat.

St. Louis ribs, also known as St. Louis-style spareribs, are flat, meaty rib bones from the pig’s belly under the breastbone. This cut has more meat than baby back ribs and more fat, which enhances their flavor. After removing the ribs from the pig’s belly, producers trim the connective tissue surrounding the meat, leaving a rectangular-shaped rib rack.

These ribs follow a prep and cooking style that is signature to St. Louis, a major city in Missouri. Rather than slow-cooking BBQ style—applying a dry rub to the meat before smoking it for extended periods—barbecuers typically start by cooking St. Louis ribs flat on the grill before covering the meat in a thick layer of sweet, sticky barbeque sauce.

This preparation method works for any type of dry rub and flavoring:

• Remove the membrane: Lay your rack of ribs on a flat surface. Slide a knife between the meat and the thin, slippery membrane, which is too tough to consume. Lift the knife to pull the membrane away from the meat. If you can’t remove it in one pull, break it off in sections.
• Season: Apply a small amount of vegetable oil to the ribs, followed by a generous amount of dry rub. Use a classic BBQ marinade with paprika and chili powder or a simple mix of garlic powder and black pepper. Include kosher salt in the spice rub to help tenderize the meat and achieve a nice crisp.
• Marinate overnight (optional): Marinating the meat overnight in the fridge maximizes flavor, but if you’re short on time, let the ribs soak in the marinade for at least an hour before cooking.
• Cook: The low-and-slow cooking method allows the meat to absorb the woody flavors of the BBQ smoker. Set your smoker to 225 degrees Fahrenheit and allow your smoked ribs to cook for three hours.

While you can purchase St. Louis ribs without the rib tips and cartilage at the grocery store, they will be more expensive. Here’s how to prepare a rack of St. Louis ribs:

• Remove the membrane and cartilage: Lay your rack of ribs on a flat surface. Using a sharp knife, slice along the thickest part of the ribs, cut across the joint, and remove the tips and excess cartilage from the rack. Slide a knife between the meat and the thin, slippery membrane, which is too tough to consume, then lift and pull it away from the rack. If you can’t remove it in one pull, break it off in sections. Hold the membrane with a paper towel to keep it from slipping.
• Season: Select your choice of seasonings for the spice rub. Prep the meat with vegetable oil, so the rub adheres to it. Use a classic BBQ rub with paprika and chili powder or a simple mix of garlic powder and cayenne pepper; however, St. Louis-style rib rub recipes often feature coriander, brown sugar, and dry mustard.
• Marinate overnight (optional): Marinating the meat overnight in the fridge maximizes flavor, but if you’re short on time, let the ribs rest in the marinade for at least an hour before cooking.
• Grill: For a traditional St. Louis-style cook, preheat your grill to 350 degrees Fahrenheit and place the charcoal on the left or right side of the grill. Lay the racks down on the center of the grill and allow them to cook for a half hour, then remove the ribs from the grill and slather them with apple cider vinegar. Enclose the meat between two sheets of aluminum foil and return it to the grill to cook for thirty more minutes.
• Sauce the ribs: Baste the ribs in barbecue sauce, then grill for one more hour or longer. When they sit on the heat long enough, the succulent, flavorful meat becomes tender enough to fall off the bone.

With proper preparation, baby back ribs and St. Louis ribs offer tender, juicy meat, but these two rib styles vary in a few ways:

• Shape: Baby back ribs have a distinctive curved shape, as the ends of the bone turn upward, and the meat on these ribs cover above and below the bone. St. Louis ribs are straight and flat, with the meat concentrating between the bones.
• Amount of meat: Baby back ribs have less meat per bone than St. Louis ribs. While a rack of baby back ribs usually weighs between one to two pounds, a rack of St. Louis ribs weighs two to three pounds.
• Flavor: Baby back ribs have leaner meat since they come from the pig’s loin. Therefore, if overcooked, baby back ribs lose their flavor and become dry. However, baby back ribs taste juicy and tender when prepared properly with an adequate slathering of BBQ sauce.
• Fat content: While St. Louis cut ribs have tougher meat than baby back ribs, they have higher fat content and more marbling, giving the meat a distinct pork flavor and reducing the amount of seasoning needed to flavor the ribs.

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