The sirloin is a desirable cut of beef because it is lean, yet full of flavor. Located between the tender short loin and the tougher round, three primary cuts or steaks are derived from the boneless portion: the top sirloin, the tenderloin and the bottom sirloin. Each steak lends itself to a variety of preparations, though they vary in terms of tenderness and cost. A little education about each cut can help you decide which cut is appropriate for the meal you have planned and for your budget.
Top sirloin is prized for its relative tenderness. A continuation of the muscle that is the short loin, the top sirloin is a supremely tender cut. Because the top sirloin is desirable it is priced accordingly. This tender cut is best grilled or broiled, but can also be pan-fried to perfection. Steak aficionados recommend cooking top sirloin to a medium-rare doneness, or until it reaches an internal temperature of 135 to 140 degrees Fahrenheit.
The tenderloin is the most prized of all three cuts of sirloin. Like the top sirloin, it is also a continuation of the short loin, but its location near the kidneys makes it extremely tender, as the muscles in this area do not perform a lot of work. The tenderloin is the most expensive cut available and is often reserved for special occasions. This is where filet mignon is derived from. Because the cuts are lean, they are often wrapped in bacon to bard them and seal in moisture while they cook, and are best prepared by broiling or grilling, cooked to a medium-rare doneness.
The bottom sirloin is the least desirable of all three sirloin cuts, but is the least expensive. Found near the less tender sirloin tip near the round, bottom sirloin steaks can be tough and have gristly fat. They can be prepared by grilling or broiling like the other two sirloin cuts, but the results will be significantly tougher. Bottom sirloin is best cooked slowly over longer periods of time in order to become more tender, or used as stew meat or ground into hamburger.
Internal Cooking Temperatures
The U.S.Department of Agriculture recommends cooking steaks until they reach an internal temperature of 145 F with a resting period of at least three minutes after cooking. The USDA also recommends that hamburgers reach an internal temperature of 160 F, no resting time necessary.