Bottom round roast, commonly called rump roast, is taken from the rump portion and hind leg of beef so it's naturally a very tough cut of beef. While naturally tender cuts such as rib roast and tenderloin can be cooked fast, you must braise bottom round roast over a long cooking time to make the meat fork-tender.
A Tough Cut
As a cow walks, it exercises its hind legs and builds up muscle, which translates into tough muscle fibers in the bottom round roast. This lean meat tends to dry out while cooking, especially when cooked over high, dry heat. Bottom round roast contains connective tissue and collagen that are tough and chewy when cooked fast, but when cooked slowly at a low temperature, the tissue breaks down and the collagen renders into smooth, melt-in-your-mouth gelatin.
Tender cuts of meat require little more than a sprinkle of dry spices for flavoring, but tough cuts such as bottom round roast benefit from marinating for at least 12 hours. A marinade typically contains a fat such as olive oil, an acidic ingredient such as vinegar or citrus juice and a blend of herbs and spices. The acid in marinade helps break down tough meat fibers to make the bottom round roast tender. You can make your own marinade or purchase a bottled marinade from the grocery store. Place the bottom round roast in a large storage bag and pour the marinade over the top. Seal the bag tightly and place it in the refrigerator to marinate overnight.
A long cooking time in an oven with dry heat can dry out the roast, making it flavorless and tough to chew. Tough meat cuts such as bottom round roast are best when braised to provide moist heat and help the meat retain moisture. Braised beef roasts are generically referred to as pot roasts. You might start by searing the meat in a bit of oil to brown the outsides, working in a cast iron skillet or an oven-safe pan such as a Dutch oven. After searing the meat, add enough water or beef broth to cover at least one-third of the roast and transfer it to the oven. Spoon the liquid over the roast periodically as it cooks to keep the meat moist throughout.
Temperature and Time
Bottom round roast should be cooked at a maximum of 300 degrees Fahrenheit or lower to allow the collagen and connective tissues in the meat to break down. The length of time really depends on the size of the roast and the actual temperature; the time increases as the temperature decreases. A typical bottom round roast that weighs 3 to 4 pounds should be slow roasted for about 4 hours to cook to well-done with an internal temperature of 165 to 170 F. You can even make the roast in a slow cooker, which takes roughly 7 hours on the low heat setting. While you might typically eat beef at medium-rare or medium doneness, this doesn't allow enough time to break down the collagen, connective tissue and tough meat fibers.
- Texas Beef Council: Cooking School: Beef Round Bottom Round Roast and Steak
- Cook's Illustrated: Classic Pot Roast with Root Vegetables
- Cattlemen's Beef Board and National Cattlemen's Beef Association: Braising/ Pot Roasting
- The Kitchn: Food Science -- Why Tougher Meats Make Good Braises
- The Kitchn: Food Science -- Braising: Best Cuts of Beef for Braised Dishes
- Serious Eats: The Food Lab's Guide to Corned Beef and the Science of Simmering
- Betty Crocker: Timetable for Roasting Meats
- Mr. Food: Melt in Your Mouth Roast
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