Important Tip: Roast is a tougher cut of meat and needs to cook long enough to break down the connective tissues. If you need to slice the meat and can't pull it apart with a fork, it hasn't cooked long enough. While it's still technically safe to eat, it will be tough and chewy, and you'll probably either never serve a pot roast again or think that this is just a terrible recipe. :) Oven temperatures vary, and if, after the recommended cooking time has passed, a fork stuck into the top of the roast doesn't cause it to shred, the solution is to cook it for a bit longer.