Rump roast isn't fast food. Plan on four hours minimum, and up to 10 hours to make it fall-apart tender. As you might expect, a rump roast comes from the back end of a steer. Also known as bottom round, this cut of beef needs long slow cooking in liquid to make it tender and flavorful.
In a slow cooker, a rump roast needs 8 to 10 hours on low heat to become fork tender. This may seem like a long time, but keep in mind that you won't need to tend it at all. Add 1/2 to 1 cup of liquid, such as water, red wine or beef broth, to the pot so the roast doesn't dry out and you can walk away for the day. The liquid should partially cover the roast, but not submerge it. Keep the lid on the entire time.
To slow-cook a rump roast in the oven, set the oven to 250 degrees Fahrenheit. At this temperature, the roast will cook in about 4 hours. Place the roast in an oven-proof pot or Dutch oven with a lid. Add 1/2 to 1 cup of broth or red wine, so that the roast is partially covered. Cover the pot with the lid or foil. Check the roast occasionally to make sure the liquid isn't simmering. Also take that opportunity to add more liquid if necessary.
In addition to several hours of cooking time, allow a few extra minutes to brown the roast. Browning isn't absolutely necessary, but it will help seal in juices and create better flavor. Heat a bit of oil in a saucepan on medium-high or high and sear the roast on all sides, just until the roast is golden-brown, but not cooked through. Transfer the roast to a covered pot or slow cooker to finish cooking it.
The first sign you'll have that the roast is done is the aroma filling the kitchen. The roast will be a dark brown or gray color and fall apart when you dig into it with a knife or fork. Beef should be cooked to at least 145 F, according to the United States Department of Agriculture, to ensure food safety, but to cook a roast until it falls apart, you'll need temperatures closer to 180 F.
- Not Your Mother's Slow Cooker Cookbook; Beth Hensperger, et al.
- Fine Cooking: Slow-Cooked Pot Roast With Mustard & Horseradish Gravy
- Kentucky Beef Council: Successful Slow Cooking
- Food Safety.gov: Safe Minimum Cooking Temperatures
- Meat: A Kitchen Education; James Peterson
- Jupiterimages/Stockbyte/Getty Images