Microwave Myths

Microwave oven myths
This is the first part of a short series on microwave ovens.

Note: Many people believe that microwaves ruin your food and your health. So far, these claims have not been proven. But if microwaves make you uncomfortable, feel free to explore other articles on the site.

I use my microwave for casseroles, quiche, vegetables, fruits, pies, soups, meats, rice, lentils, beans and even some cakes. It uses less electricity than a conventional oven, and keeps the house cooler.

Microwave cooking is different:

  • Microwaves cook from the outside in, so the center takes longer to cook.
  • They heat only moisture in the food, so microwave-safe utensils don’t get as hot. Neither does the kitchen. Still, use pot-holders.
  • Edges of food may get crisp, but not brown.
  • Foods continue cooking for a few minutes after being removed.
  • Small amounts of food can be heated or cooked quickly.
  • You need microwave-safe utensils. You probably already have many things you can use.
  • Larger amounts of food take proportionally more time to cook.
  • It’s easy to overcook food in the microwave, but all microwaves turn off automatically. With experience, you’ll learn when to check the food.
  • Utensils don’t scorch, making microwaves ideal for sauces, chocolate, and fruit.

How do microwaves work?

Microwaves work by radiating microwave energy into food. This energy only heats up the moisture in food, so dried foods may burn or explode.  The waves pass through glass, ceramic, plastic and paper, but metal deflects them.

When you set the microwave to High or 100%, the motor and turntable work continuously. On lower settings, the microwave stops periodically. Just as with many other appliances, the microwave heating element has only an off or on setting and nothing in between.

If you choose the 80% setting, or Medium-High, the microwave operates for 80% of the time and pauses for 20%. In theory, the food cooks more slowly and gently because microwaved food continues to cook even when the microwave element is off. But I never use any setting other than High. This  means checking food more frequently, especially while you are learning. But I don’t find that lower settings improve the quality of the food.

Defrosting in the microwave

For defrosting, a lower setting helps keep food from getting too hot. Because the microwave warms up food as it defrosts and attracts bacteria, microwave-defrosted food must be cooked immediately. While defrosting, check and turn food frequently.

A slow defrost in the refrigerator is safest. It helps keep other foods cold and saves on your electric bill.

Do microwaves undercook food?

Microwaves using higher wattage cook food faster, but those with lower wattage work equally well. Whatever the wattage or setting, check to make sure food is cooked through as you would with any other kind of food. Some foods require different techniques—chicken must be turned from top to bottom and outside to inside to cook evenly.  But microwaves don’t deserve their reputation for undercooking food.

Choosing Microwave Utensils

You might also enjoy the following:

Do You Need a Second Freezer?

Making the Most of Your Conventional Oven

Try making Bread Pudding in the microwave.

Simple Microwave Recipes

Marinated Nile Perch in the Microwave

image: xJason.Rogersx


  1. microwaveguru says

    There are some errors in your comments. Microwaves do the heat water in foods, but they also heat other things. For example, the glaze on ceramic dishes can become extremely hot unless it has been properly formulated. This can cause serious burns – in my lab we measured temperatures up to 300 F on glazed ceramic coffee cups even though they were labeled “Microwave Safe”. Also, you mentioned dry food burning, which is true – so it is obviously heating in spite of not having water or moisture. In fact, since this is energy transfer, anything, including glass or sand will eventually heat – the glass will melt, the sand will form glass… While you are correct that the microwaves heat from the outside, the issue is extremely complicated and may result in the energy concentrating in the center and actually heating the center much faster or to a higher temperature than the outside, which is always cooler because of the cold air in the oven. This explanation could go on, but would be too long for here.

  2. Guru: Thank you for your comments and clarification. I will be quoting you next week when I talk about utensils.
    I thought soft centers, like jelly donuts, were a problem because of the moistness.

  3. The exploding liquid thing happened today at work, and although i wasn’t injured, i was very curious as to what exactly had occurred. Thanks for clearing it up cooking manager!