It is a common misconception that chuck roast gets more tender the longer you cook it. In fact, chuck roast is best cooked to an internal temperature of 145 degrees Fahrenheit, at which point it will be both flavorful and tender. If you cook it any longer than that, the meat will begin to dry out and become tough. So if you're looking for a perfectly tender chuck roast, be sure to pull it from the oven or grill at 145 degrees Fahrenheit.