The most commonly found pork ribs in the supermarket, spareribs are thick and meaty ribs from the pork belly, so named because they're what's leftover (or spare) after the bacon has been cut away. There are two cuts of spareribs: standard and St. Louis.
Standard ribs, or a full slab slab of spareribs, consists of the front, or belly ends, of eleven ribs and the cartilage that connects the ribs to the breastbone. You may see a recipe calling for St. Louis-cut spareribs. This means the butcher removes the sternum portion and much of the connecting cartilage, leaving a narrower, slab of ribs. Cutting off this strip of gnarled meat makes the ribs a more uniform shape, so they cook more evenly. They're also easier to cut into individual ribs after cooking. Spareribs come from the relatively tough but incredibly succulent belly portion of a hog, so they're best cooked slowly and gently, which is why they're often a first choice for slow-cooked barbecuing and braising.
1 slab = 2 to 3 lb.
Substitute baby back ribs.
As when buying bacon, look for a good ratio of meat to fat; the fat will baste the meaty portion as the ribs cook.
Trim off any excess fat and remove the membrane (also called silverskin) that runs the length of the boneside of the rack so that seasoning and smoke can better penetrate the meat. (Some racks are sold with this already removed.)
Ribs should be refrigerated or frozen. You can also wrap and freeze cooked ribs.