Differences Are Usually Subtle in Microwaves

For a long time people delayed buying a microwave oven because it didn’t brown a steak and could only bake one dish at a time. They were put off by the price--an oven could cost up to $600--and were reluctant to give up counter space. And there was the concern over safety.

But reluctant buyers began to be convinced by some of the changes made by microwave-oven manufacturers. By the end of 1984, 40% of American households had microwave ovens.

If microwave sales continue to grow at the current pace, the U.S. Industrial Outlook 1985, published by the Department of Commerce, predicts that the market will be saturated within the next five years.

With nearly 40 different microwave oven manufacturers looking for customers, fierce price competition is expected. By shopping around, it’s possible to find a “bare-bones” microwave oven for as little as $139, but the “all-frills” design can go as high as $500.

For consumers who are considering adding a microwave oven to their kitchen, boat or camper, here is the latest update.

The decision of which oven to buy is a personal one, to be made after considering the type of cooking you do, the amount of space you are willing to devote to the oven and the money you can spend.

The differences among ovens are subtle. According to a rating done by Consumer Reports in May, 1983, “The differences in performance, speed and energy use were slight.”

The basic component in a microwave oven is the magnetron tube, a type of vacuum tube that converts electrical energy into high-frequency microwave energy capable of generating heat within food for rapid cooking.

These microwaves enter the oven from the top or the top and bottom of the oven and bounce around, reflecting off the sides and bottom. The waves are directed by a fan, or stirrer blade, which is at the top.

Electromagnetic Wave

The microwave itself is an electromagnetic wave of frequency between 300 and 30,000 megahertz and is similar to infrared light and radio waves.

The bouncing microwaves strike moisture particles in the food, causing water molecules to vibrate. This movement creates incredible friction that produces heat, sort of like rubbing your hands together to keep warm.

Microwave cooking is moist-heat cooking. The things that cook best are those with a high percentage of water, such as vegetables, casseroles, stews, fish, soups and sauces.

There are drawbacks. Because microwaves are less attracted to dry foods, when a dish of spaghetti and tomato sauce is removed from the oven, the sauce may be boiling and the spaghetti tepid.

For more even cooking, a dish must be turned once or twice. When removed from the oven, it must “sit” for several minutes, and during this time the food becomes evenly hot.

There is no significant difference in nutritional value between foods cooked in a microwave oven or by conventional means.

Conventional ovens are set at temperatures; microwave ovens are set at power levels. High or full power in all microwave ovens is 100% power, whether the output of the oven is 400 watts or 700 watts. When a recipe calls for half-power, this can be 200 watts or 350 watts, depending on what full power is.

Charts are available that show different settings on a variety of microwave ovens so that you can interchange recipes developed for a specific wattage oven by cooking the food for a longer or shorter period of time.

The time it takes for food to cook is directly related to the amount of food cooked and the amount of wattage the oven puts out. The higher the wattage, the shorter the cooking time.

An oven with 700 watts will cook about 25% faster than one with only 500 watts. The more food placed in the oven, the longer it takes to cook it.

Some large ovens have as many as 10 power levels; others have three or four, which, according to Consumer Reports, is all that is really necessary for most cooking.

Microwave ovens are manufactured in roughly three sizes, and the one chosen depends on what it will be used for--family meals, defrosting, frozen entrees, leftovers or entertaining.

The compact size has a 400- to 500-watt power output and is suitable for one or two people. Its interior capacity is 0.5 to 0.6 cubic feet, and its main function is defrosting and reheating. It can easily fit under a kitchen cabinet.

The mid-size oven ranges from 0.8 to 1 cubic foot and puts out 500 to 600 watts of power. This size is suitable for small families for defrosting, reheating and cooking small dishes.

Large families or people who like to cook might opt for the 1.5 to 1.53-cubic-foot size, which can hold larger dishes. With 650 to 700 watts, these ovens cook food faster.

Some units come with two ovens--a built-in conventional oven below the burners and a microwave oven above.

Another popular choice is the microwave oven in combination with a convection oven. The convection oven browns the dish, then it is cooked quickly using microwave energy.

Since microwaves do not penetrate metal pans, food will not cook in them. The easiest way to determine if a non-metal dish is microwave-proof is to heat it on high, or 100% power, for 30 seconds. If the dish becomes too hot to touch, don’t use it.

Understanding your own cooking style will help you decide on the appropriate oven. For those who like to have dinner waiting for them when they walk in the door, a microwave with a high-tech touch-control panel makes it possible to leave frozen food in the oven in the morning and come home to food that has been automatically defrosted and cooked.

Cooks should realize that a small oven, designed to merely reheat food, is limited. On the other hand, many buy fancy microwaves with all the extras and wind up using them solely for defrosting and heating foods, chores a small oven can do.

Basics to Consider

Among the basics to consider while you’re shopping for an oven are:

--An interior light, to observe food while it is cooking as well as to indicate that the oven is in operation. The light also should come on automatically when the door is opened.

--An audible beep to indicate cooking is over.

--An interior that wipes clean with a damp sponge or cloth.

--A grounded, polarized three-prong plug on portable microwave ovens so that the oven can operate from a standard home outlet.

--An automatic turn-off device that shuts down the oven when circulation is blocked. Venting is necessary to keep the inside workings cool.

--An in-house service contract so you won’t have to lug the oven--they weigh up to 70 pounds--into the store for servicing.

--A horizontal center rack, which is ideal for two people who want to heat two dishes at the same time.

“It’s important to do your homework,” says Anne Howard of Sharp Electronics. “Many of these ovens have automatic features to make cooking even easier.”

But these features cost money, and the cook has to decide whether they are practical and usable.

--Like some conventional ovens, some microwave ovens come equipped with a temperature probe that will automatically turn off heat when the food has reached a certain temperature and hold it at that temperature until serving time.

--When a food sensor is programmed with the weight and type of food, it turns off the oven automatically when the food is cooked.

--The main control will be a simple timer dial or an electronic digital display. The dial control is less expensive and reduces the cost of the appliance, but it cannot be set manually for readings of less than one minute.

--Some microwave ovens can be purchased with a built-in turntable that revolves during the cooking period so that the food is equally exposed to microwaves on all sides.

--Food cooks so quickly that it has little time to brown and rarely gets crisp. Manufacturers get around these deficiencies by supplying browning dishes, or heating elements for use when cooking steaks, chops and burgers.

The final consideration is what brand to buy. Once you decide on size, features and how much money you want to spend, shop around for the best buy.