The microwave is one of the most misunderstood appliances in the kitchen. There are a few basic facts to keep in mind: It is not a substitute for the stovetop and oven. It does not cook foods from the inside out. It cooks some things very well, but it cannot be used for all of your cooking needs.
In a microwave oven, electricity is converted into microwaves by the magnetron; the waves are spread throughout the oven cavity via a revolving "stirrer fan" in the oven. With a tight-sealing door and at least two interlocks, todayΓÇÖs ovens are well within the U.S. Bureau of Radiological HealthΓÇÖs safety standards. Microwaves can penetrate glass, ceramics, paper, and plastic, but they are deflected by metal, which is why microwave oven interiors are lined with metal.
When these aimless, fat little waves are scattered about the oven cavity they behave like billiard balls gone awry, bouncing off the walls and careening about until they land on something that is moistΓÇöwater or food. At that point the waves will penetrate only I to 1 1/2 inches deep, but in so doing, they cause the water molecules they touch to vibrate, causing friction and thus producing heat. Once the water molecules are moving about, the food cooks by simple conduction, from the outside to the inside. Microwaves are the energy source, but the cooking process is the equal of what happens to food in a skillet over a burner or in the cavity of a hot oven: The heat is conducted from the outside of the food to the interior. But unlike in conventional cooking, it is the excited molecules that transfer the heat to the center of the food, rather than a heat source below or above it. Therefore foods do not brown in the microwave oven, and the devices that claim to brown food are usually ineffective and can be dangerous by concentrating heat on plastic surfaces.
Ingredients that have a high water contentΓÇömost vegetables, virtually all greens, fish, and fruitsΓÇöcan be quickly cooked in a microwave oven. They will have a steamed quality to them, but without the excess moisture steam might leave behind. Fresh sweet corn cooks in seconds, artichokes in minutes, and a big winter squash requires only a fraction of the time it takes in a steamer or thermal oven. Wilted spinach saladsΓÇöfrom cooking the bacon to finishing the dishΓÇöare ready to eat in moments. Peeling tomatoes or peaches is simple after a few seconds in the microwave, and, for melting cheese or chocolate or butter, nothing could be tidier.
In addition, microwaving fruits and vegetables preserves more nutrients than practically any other cooking method because you use little or no nutrient-leaching water and because it cooks faster than any other method. Defrosting in a microwave is healthful too, because it is fastΓÇöno meat or poultry sitting at room temperature encouraging bacteria to grow. Also less butter, oil, or other fat is required for microwave cooking, because these ingredients are used solely as flavorings, rather than to prevent sticking.
