When shopping for a good steak to grill, it helps to understand some anatomy. The first lesson is that meat is muscle, and the relative condition of the muscle determines the taste and tenderness of the meat. A protected, little-used muscle such as the tenderloin will be tender and finely grained with a relatively mild flavor, while a stronger, well-exercised muscle will be tougher and more flavorful.
The rib section begins just behind the shoulder (or chuck) and runs to the bottom of the rib cage. Positioned between some of the toughest (chuck) and most tender (short loin) parts of the animal, the well-marbled rib meat has a unique balance of flavor and tenderness that real beef lovers revere. This location also means that the two ends of the rib offer rather different steaks. The steaks from the end closest to the short loin (known as the small end) are the tenderest and have a neat, well-defined eye muscle; steaks from the shoulder end (the large end) may be slightly tougher, with a less well-defined eye.
The short loin
The short loin runs from the last rib to the top of the hip bone, and the only bone in the short loin is the backbone itself. Sitting high up on the animal, the short loin is one of the least exercised muscles of all and, therefore, it’s the most tender. Unlike the rib, which has one primary muscle, the short loin has two: the tenderloin and the top loin, separated by the backbone. The top loin is actually a continuation of the ribeye muscle and has many of the same characteristics. The tenderloin muscle, tucked beneath the backbone, is noticeably more tender and fine-grained. A bit of both muscles is included in some steak cuts. Porterhouse steaks have the most tenderloin (at least 1-1/4 inches in diameter); T-bones have the least (as small as 1/2 inch in diameter). Top-loin steaks are created when the butcher first removes the entire tenderloin to sell separately, leaving behind only the top-loin muscle.
The sirloin is the hip section, between the short loin and the round, and it comprises various muscles configured around the pelvic bone. Several good-tasting, moderately tender steaks come from the sirloin (including the butt end of the tenderloin), but it is difficult to generalize since the characters of the individual muscles differ quite a bit. You’ll find both boneless and bone-in sirloin steaks; the bone is often referred to as the pin, flat, round, or wedge bone. Good choices for grilling are top butt, top sirloin, center-cut, tri-tip, triangle, or culotte. These cuts are a good value, too—often less expensive than steaks from the rib or short loin.
Unlike the naturally tender “middle meats” (rib and short loin), flank steak is a well-exercised, naturally lean muscle from the underside of the animal. Easily recognizable by its flat, oblong shape and its distinctive grain that runs lengthwise along the muscle, flank may lack tenderness, but it more than makes up for it in flavor. To prepare good flank steak, never cook it beyond medium and always slice it thinly across the grain to make it more chewable. Skirt steak, sometimes confused with flank steak, is a long, thin muscle that’s fattier and more tender than flank; it comes from the plate.