Pork spareribs come from the chest of the pig, and are attached to the sternum (breastplate) before removal. They are the meatiest of the ribs, and have the most flavor. Back ribs, or “baby” back ribs (AKA loin ribs) come from the central section of the pig, beginning where the sparerib ends, almost connecting to the backbone. They are much less meaty, smaller, less flavorful, more expensive, more tender (but much more likely to be overcooked and dried-out since they have less self-basting fat), and more likely to be glazed with some kind of gloppy sauce. Baby backs are the rib fodder butchered for your neighborhood national chain restaurant menu.
“Country style ribs” aren’t technically really ribs, but are cut from the blade end of the pork loin…they do have sections of the blade bone running through them, and come from an area right next to and above the head end of the spareribs. They are good and meaty, if a little lean, and grill better than they barbecue, but they are technically not ribs.
A whole rack (AKA “slab”) of spareribs has the breast bone and cartilage intact, and any meat cooked with bone and costal (rib) cartilage equals more flavor. If the breast bone and cartilage have been trimmed off, the rack is called a St. Louis rack. Apparently in St. Louis they don’t like flavor. If they take off the skirt of meat that lies on the back side of a rack of St. Louis ribs, it’s then called a Kansas City rack (AKA: KC Cut, Colorado Cut, South Side Cut). This whittles a perfectly good rack of spareribs down to the size of a puny baby back slab. People in Kansas City apparently love bulimic racks of ribs, and like flavor even less than residents of St. Louis. Some boneheads argue that the definitions of St. Louis and Kansas City are reversed; we avoid pointless arguments. Both types are suckacious manglings of the regal sparerib.
Spareribs are sold wholesale by weight, and have their own size terminology: “3½ and down” is a rack that weighs less than 3 and a half pounds, meaning it came from a younger and more tender pig. A “3 to 4” or a “3 to 5” is a slab that weighs between 3 and 4 pounds or 3 and 5 pounds. The bigger the slab, the older the animal, and the lower and slower it should be cooked to maintain tenderness. A full rack of spareribs should have between 11 and 14 ribs, and should feed between 2 and 4 eaters, depending on their rib-storing capacity. Figure on losing about 25% of your total rack weight when you cook a slab of ribs.
Fresh is always better than frozen. All-natural or organic is always better than water-injected, antibiotic and/or hormone-laced pork. Reject “enhanced” slabs…packed with water, sodium phosphate, flavorings, and tenderizers…you want real meat. Avoid “shiners”: ribs that have been trimmed so close by the meat processors that the bones show through…these will have little actual meat to consume. Look for slabs that have good meat coverage and nicely-trimmed fat shells. Older, traditional breeds of pigs like the Berkshire and Duroc, which have more fat marbling running throughout their flesh, are preferred over the modern mutant ‘lean’ pigs.
Regardless of how you plan on cooking the ribs, or what you might be flavoring them with, the membrane on the back side of the ribs should be removed before seasoning. The sheath-like membrane covers the back side of the slab. Once removed it allows the seasonings to penetrate the meat easily, and makes the rack more tender. To remove, use a blunt-edged knife and pry up one corner of the membrane. Using a thin towel or a paper towel, firmly grasp the corner of the membrane and pull it off. One removed, the rack is called a “skinned” slab. Some folks prefer to make a series of shallow cuts with a sharp knife through the membrane. We like them skinned.