Most of you have experienced it. You cooked that expensive rib roast to 140 degrees so that it will be done perfectly medium rare. You let it rest, because everyone tells you to let it rest. While the meat is resting, the inside of the meat is still cooking. Although your thermometer tells you the inside is 140 degrees, the outside of the meat is close to 212 degrees. The energy from the outside continues to travel inward as the meat is resting. With thick cuts of meat, you have to pull the meat a few degrees less than you normally do. After resting for 15 minutes or so, it should be exactly where you wanted it to be.
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