When you open a microwave during its cooking cycle, you may sometimes observe that the food continues to heat up even though the microwaves are no longer being emitted. This phenomenon is known as "carryover cooking" or "residual heat."
Carryover cooking occurs because microwaves heat food unevenly. During the cooking process, the microwaves penetrate the food and excite water molecules, fats, and other molecules, generating heat. However, this heat is not distributed uniformly throughout the food.
When you open the microwave door, the microwaves immediately stop, and the energy absorption ceases. However, the heat that has already been generated in certain parts of the food is still present. This stored heat continues to transfer through conduction from the hotter areas to the cooler areas of the food, leading to further cooking even without the microwave's active energy.
The amount of carryover cooking depends on various factors, including the initial temperature of the food, its composition, and the duration of the cooking cycle. Dense or thicker portions of the food tend to retain more heat and may experience greater carryover cooking.
To mitigate carryover cooking, it is advisable to allow a short resting period for the food after removing it from the microwave. This allows the heat to distribute more evenly within the food, minimizing the temperature disparity and reducing the potential for overcooking.
It's important to exercise caution when handling food from the microwave, as it may still be hot even after the microwaving process has ended. Use oven mitts or other protective gear, and test the temperature of the food before consuming or further handling it to avoid burns.