Health Encyclopedia

Warming Up to the Microwaves

Cool, clean, and quick, microwave ovens help feed millions of U.S. households. More often than not, we use them to make popcorn, reheat coffee, "fry" bacon, or "bake" a potato.

When we cook a complete dinner in the microwave, the meal usually comes from a box. If you've read the package of your favorite entree, you may have gulped at the fat content or cringed at the carbohydrate and sodium levels. It doesn't have to be that way.

Strengths and weaknesses of microwave cooking

First, you need to think about what microwave ovens do well and don't do well. Skip the meat and pass on boiling pasta, but rice turns out nice.

Despite "browning" dishes, a plain microwave isn't the best way to cook a steak. Some ovens, however, combine microwave and convection cooking that lets you brown, bake, and roast food in one oven.

But regular microwaves are superb for seafood and vegetables. You can cook shellfish in less than five minutes, using the same bowl you'll put on the table. Vegetables keep their color, crispness, and water-soluble nutrients because you can microwave them using just the water that remains after rinsing.

You also can cook with very little fat, adding only the best olive oil or a little butter for flavor just before serving.

Here are some tips on real cooking in your microwave:

  • Read your microwave's instructions. You'll learn about a lot more than wattage. Lower wattage cooks slowly while higher wattage cooks more quickly.

  • Use the proper paper and plastic wrap. Not all are suitable for microwaves. Recycled paper products can contain metal flecks that may ignite or cause "arcing," the microwave term for sparks.

  • Pay attention to details. Small variations in the size and amount of food or the size and shape of the dish can make big differences.

  • Wait before eating. Portions of the food may be extremely hot after you take it out of the microwave. That's the time to add garnish or warm up a roll.

  • Don't forget potholders. The microwave won't heat the dish—but hot food in the dish will.

Microwave mechanics

A normal oven heats food by exposing it to hot air and thermal radiation—cooking the food from the outside in. A microwave oven heats the water within the food—cooking the food relatively evenly throughout although the outside still cooks slightly faster.

A vacuum tube called a magnetron creates intense microwaves in the cooking chamber. These high-frequency electromagnetic waves cause water molecules to vibrate back and forth very rapidly. As they twist, they rub against one another, and friction heats them up. The water becomes hot and cooks the food.

A microwave is safe if you use and maintain it properly. If you drop the oven or damage its door in some way, have it checked for leakage that might interfere with pacemakers or other medical devices.