Does Microwave Food Cool Faster?

How Microwaves Cook

• Microwaves cook by sending waves through the food. These waves cause the water molecules in the food to vibrate, which heats the food. Foods greater than 1-inch-thick will require turning or stirring during cooking because microwaves cannot penetrate deeper into the food than 1 inch, according to "Why Do Donuts Have Holes?: Fascinating Facts about What We Eat and Drink" by Don Voorhees. This is why the center of microwaved foods might remain cold after the outside is hot, especially if you did not turn or stir the food during heating.

How Ovens Cook

• Ovens cook by two methods: conduction and convection. Convection ovens circulate this hot air with fans, but the hot air will naturally move in a conventional oven as the hottest air rises to the top of the oven and cooler air sinks to the bottom heating element where it warms and rises. These invisible convection currents surround the food, slowly cooking it from the outside to the inside. The food is also in direct contact with the cookware, which becomes hot in the oven and conducts heat to any food directly in contact with it. Ovens heat food more deeply and evenly than microwaves from using these two heat transfer methods.

Food Cooling

• Foods cooked in a microwave, compared to those in an oven, probably did not reach the same internal temperature. While microwave foods might feel hot on the outside, the part of the food deeper than 1 inch will not be as warm. Oven cooked foods have been exposed to heat long enough for the heat to reach the deepest portion of the food, and are more likely to be hotter internally than microwaved foods, notes Robert L. Wolke in "What Einstein Told His Cook: Kitchen Science Explained."

Preventing Cooling

• To keep microwaved foods from cooling too quickly, carefully follow the instructions for the food. Rotate or stir the food at least once during cooking and leave solid foods in the microwave, covered for at least two minutes after the microwave shuts off for the food to continue to cook. Use a food thermometer inserted in the center of the food to verify that it reached the desired internal temperature. Keep foods heavily insulated after removing them from the microwave to keep the heat inside the food.