Allowing for prep times, which includes searing the meat on all sides before putting into the slow cooker, it takes between 8 and 9 hours to cook a roast, such as a beef pot roast, on the low setting. Cooking the roast on the high setting can reduce the cooking time by as much as half. Roasts are typically made in a slow cooker with vegetables in a broth, which can be used to make a gravy.
A beef pot roast, usually made with chuck, becomes extremely tender when cooked slowly. A 3 1/2-pound roast will make up to 10 servings. In most cases, the meat will be fork tender. However, use a meat thermometer to determine the meat's doneness, which should register 145 degrees Fahrenheit for medium rare and 160 degrees for medium. Remove the roast from the slow cooker and allow the meat to rest 10 minutes before serving.