Cooking ribs in the oven at 250°F is a great way to get flavorful, fall-off-the-bone ribs. At this low temperature, the ribs will cook slowly which allows the fat to render and the meat to become incredibly tender. The cooking time can vary quite a bit depending on the size and cut of the ribs.
Baby Back Ribs
Baby back ribs are the smallest cut of pork ribs. They are taken from the upper part of the ribs near the spine and include 11-13 bones. Due to their smaller size, baby back ribs typically take less time to cook than other rib cuts. Here are general guidelines for oven cooking times at 250°F:
- 1.5 – 2 lbs baby back ribs: 2.5 – 3 hours
- 2 – 2.5 lbs baby back ribs: 3 – 4 hours
- 2.5 – 3 lbs baby back ribs: 4 – 5 hours
Spare Ribs
Spare ribs come from lower down the rib cage and include more bone, fat, and cartilage than baby back ribs. They tend to be longer and meatier. Spare ribs require more time in the oven at a low temperature like 250°F. General oven cooking times are:
- 2 – 3 lbs spare ribs: 4 – 5 hours
- 3 – 4 lbs spare ribs: 5 – 6 hours
- 4 – 5 lbs spare ribs: 6 – 8 hours
St. Louis Style Ribs
St. Louis style ribs are a trimmed version of spare ribs. The breastbone, cartilage and rib tips are removed which leaves a neat, rectangular slab of meat and bone. Since there is less fat and cartilage, St. Louis style ribs cook a little faster than untrimmed spare ribs. Here are rough oven cooking times:
- 2 – 3 lbs St. Louis ribs: 3 – 4 hours
- 3 – 4 lbs St. Louis ribs: 4 – 6 hours
Key Factors That Affect Cooking Time
While the times above provide general guidelines, there are several factors that can increase or decrease the necessary oven cooking time at 250°F:
- Thickness – Thicker ribs will obviously require more time than thin, bone-heavy ribs.
- Bone-in vs Boneless – Boneless ribs will cook faster than ribs with the bones still attached.
- Meat cut – Chuck or shoulder ribs take longer than loin back ribs.
- Rack vs. Individual ribs – Individual ribs will cook faster than full racks.
- Cooking temperature – The oven temperature can be increased to shorten cooking time. For example, 275°F would cook ribs faster than 250°F.
Tips for Oven Cooked Ribs
Follow these tips for flavorful, tender oven-baked ribs:
- Choose the right rib cut for your timeline. Baby backs for quicker cooking, spare or St. Louis for longer cooking.
- Remove the thin membrane from the back of the ribs for better seasoning and smoke penetration.
- Season or rub the ribs at least 30 minutes before cooking, even overnight for more flavor.
- Cook ribs on a wire rack in a sheet pan or directly on oven racks to allow airflow and drainage of fat.
- Spritz ribs periodically with apple cider vinegar, juice or broth during cooking.
- Wrap ribs in foil after a few hours of cooking to power through any stubborn tough spots.
- Allow ribs to rest for 10-15 minutes before cutting for juicier meat.
How to Tell When Ribs are Done
With the low and slow cooking method, ribs are ready when they are fall-off-the-bone tender. Here are some ways to test doneness:
- The meat has shrunk back from the ends of the bones 1⁄4 to 1⁄2 inch.
- A fork or knife inserted into the meat meets little resistance.
- The ribs flex and bend easily without breaking.
- The meat splits cleanly between the bones when bending the rack.
- The internal temperature of the meat registers 195-205°F.
Conclusion
Cooking ribs in the oven at a low temperature of 250°F delivers incredibly tender, flavorful results. Baby back ribs take 2.5-5 hours, spare ribs take 4-8 hours and St. Louis ribs take 3-6 hours depending on size. Factors like thickness, cut, and bone affect cooking times. Use visual cues like shrinkage and tenderness to determine when the ribs are perfectly cooked.