Steak is considered medium rare when its interior temperature is between 140 and 150 degrees Fahrenheit. Medium rare steaks have a warm, pink center with a small amount of red and a firm texture.
Use a meat thermometer to test the internal temperature. Cutting the meat with a knife to check the color results in the loss of juices that impart flavor to the meat. Many cooks use a touch test to determine the doneness of steaks by placing a finger in the center of the steak. If the slight indentation caused by the finger springs back quickly, the steak is medium rare. Steaks that don't give at all when pressed in the center are cooked to medium or beyond, and those that feel spongy and soft are still rare.