Tips on choosing the right cookware for microwave ovens

CHOOSING the best microwave cookware and accessories can be bewildering, given today's wide choice of brands, designs, materials, and sizes. To help choose cookware in a variety of sizes, shapes, and materials, here are tips from a technical handbook prepared by the International Microwave Power Institute, a trade association in Clifton, Va.:

Cookware shape should correspond as closely as possible to the shape of the food to be defrosted or cooked in it. This is especially important, even for defrosting.

Round is the best shape. Food may overcook in squared corners.

Ring shapes permit maximum microwave penetration. Tubes are especially important for cakes.

Straight sides allow more even penetration of microwaves than sloping sides.

Handles grippable with potholders are an important safety feature.

Boil-ups are more frequent in microwaving than with other cooking methods. Cookware should allow ample headroom.

Check the interior dimensions of the oven, and make sure the cookware is easy to put in and remove.

Cookware safe for multiple functions (freezing, rangetop cooking, conventional baking, and microwaving) is a better value than single-purpose items, regardless of original cost.

Resistance to staining, discoloring, and warping contributes to durability, including the very important dishwasher safety.

For physical reasons, weight may be important. Lighter weights represent safety features for the elderly or the very young.

``Active'' cookware contains materials that interact with microwave energy to become very hot, to attractively brown foods such as meats.

For the sake of safety, always follow manufacturer's recommendations for preheating such cookware. Overheating it can break the glass shelves in some oven models.

Microwave popcorn poppers are shaped to attract microwave energy to the kernels, and microwave popping is unsafe in other microwave cookware.

Turntables, either built-in or accessories, improve evenness of cooking and eliminate the need to turn the food as it cooks.

Special microwave thermometers that can be left in the food as it cooks are useful if the oven does not already have a built-in probe to sense whether food is thoroughly cooked.