Cooking tender meat to perfection—so that its internal temperature is just what we want—is a real challenge. Imagine that we grill a thick steak just to medium rare, 140°F/60°C, at the center. Its surface will have dried out enough to get hotter than the boiling point, and in between the center and surface, the meat temperature spans the range between 140°F/60°C—medium rare—and 212°F/100°C—cooked dry. In fact the bulk of the meat is overcooked. And it only takes a minute or two to overshoot medium rare at the center and dry out the whole steak, because meat is cooked but juicy in only a narrow temperature range, just 30°F/15°C. When we grill or fry an inch-thick steak or chop, the rate of temperature increase at the center can exceed 10°F/5°C per minute.