How long short ribs should braise depends upon the temperature they're braised at. You can braise them in an oven as low as 300 degrees, but they'll take up to 4 hours. I like to braise long-cooking cuts such as short ribs at 350 degrees. They get fall-off-the-bone tender after 2 1/2 to 3 hours. You don't want to braise at a high temperature because the meat can boil, making it tough.