Knowing exactly when your ribs are perfectly cooked can be a real challenge. With larger cuts of meat such as pork butts, steaks, or tenderloins, you can use an instant-read thermometer inserted into the thickest part of the meat to determine the internal temperature. But, with ribs, you can't really insert a thermometer. And because slabs come in a variety of weights and thicknesses, cook time isn't the best way to estimate doneness, either.
Personally, I don't want my ribs to fall off the bone. I like for them to have chew and to pull cleanly off the bone when I take a bite. How can one tell when you've reached this yummy perfection? Start by using cooking time as a general guide; go low and slow by keeping your smoker or grill temperature between 225° to 250°. Baby back ribs will take 3 to 4 hours and St. Louis-style ribs will take 5 to 6 hours. Then, check the ribs by inserting a toothpick into the meat between the bones. When the toothpick slides out with little or no resistance, you've achieved what I think is a perfectly cooked rib.
Be sure to try our Ultimate Smoky, Sweet Ribs in the June issue of Southern Living.