Slow cookers can brown meat, but the meat doesn't have the same carmelization that occurs when the food is seared on a stovetop. The resulting color is lighter when the meat is prepared in a slow cooker.
Large quantities of ground beef can be browned in the slow cooker and frozen in individual packages for future use. The meat should be broken up before it is placed in the cooker, and it should be stirred a few times while it cooks. Seasoning can be added shortly before the cooking is complete. Slow cookers should be filled between one-half and three-quarters full to prevent burning.