What are microwaves? How do microwave ovens work?

Microwaves are a form of electromagnetic radiation. They are reflected by metal, can pass through materials like glass, paper, and plastic, and are absorbed by food. Generated by an electron strip called a magnetron, they vibrate the water molecules in food at high speeds, which produces the heat that warms or cooks food.

Are microwave ovens safe?

Yes, as long as they are functioning well and used properly. Microwave ovens should always be kept clean and well-maintained to avoid poor performance or unexpected malfunctions. You should only use microwave-safe containers, which could be glass, ceramic, or plastic and should be labeled accordingly; metal pans and aluminum foil are not meant for microwave oven use, as they reflect microwaves and can damage the machine or improperly cook or heat food.  Microwave-safe containers can still become hot when used to heat foods and need to be handled carefully to avoid injury.

Are there cooking or household operations for which the microwave oven should not be used?

Microwave ovens should NOT be used for deep-frying, canning, or heating baby bottles. There are not adequate temperature controls for these functions to be safely performed in a microwave oven.

Due to the risk of fire, microwave ovens should not be used to dry or sterilize clothing or other non-food articles.

What is the best way to cook with a microwave oven?

The shape and consistency of food affects how evenly they heat in microwave ovens. Food with symmetrical shapes, especially round or oval, and with even thickness (less that 1 inch) generally heat the most uniformly. For thicker portions, better results may be obtained with reduced power for longer periods such that the outer portions don’t overcook before the center is heated thoroughly. To promote uniform cooking, arrange food items evenly in a covered dish and add some water, if the food is fairly dry, to promote more even absorption of microwaves. Bone can shield meat from thorough cooking, so, where possible, debone large pieces of meat. It is important that foods be stirred, rotated, and inverted, if possible, halfway through cooking for more even distribution of microwaves and heat throughout the food. Even if a turntable is used, it is best to place the food off-center and to stir foods top to bottom or turn foods over, if possible.

Use microwave-safe containers. Do not use foam containers for cooking or reheating foods unless labeled microwave-safe. Cover the dish with a lid, microwave-safe plastic wrap, or a clean, unprinted, white paper towel, but leave a small opening for steam to escape. Allow enough space between the food and the plastic wrap so the wrap doesn’t touch the food. The steam that is created by using a lid will help heat the food more evenly and will also help destroy any harmful bacteria.

Just as other types of ovens, microwave cooking can destroy bacteria and other pathogens; however, food can cook less evenly than in conventional ovens, resulting in cold spots, due to factors described earlier. For best results in both the quality and safety of frozen or refrigerated foods, consumers should follow the cooking instructions on product labels and observe the standing times, if provided. Adjustments to the cooking time, due to oven wattage or other factors, may be necessary to reach the desired temperature before serving. For frozen or refrigerated foods that do not have labeled cooking instructions, it is suggested that the following cooking temperatures—as recommended by the United States Department of Agriculture (USDA)—be reached in all parts of the food.

  • Ground meats: 160° F (71° C)
  • Ground poultry: 165° F (74° C)
  • Beef, veal, and lamb steaks, roasts, and chops: 145° F (63° C)
  • All cuts of fresh pork: 160° F (71° C)
  • Poultry: 165° F (74° C)
  • Eggs and dishes containing eggs (i.e. casseroles, soufflés, etc.): 160° F (71° C)
  • Fish/seafood: 145° F (63° C)
  • Foods to be reheated that have previously been cooked and cooled by the consumer (i.e. leftovers): 165° F (74° C)

After the cooking time has ended and proper standing time has been allowed, the temperature of the food should be checked. Remove the food from the microwave and use a food thermometer to check the food in several places to ensure that a safe temperature has been reached throughout. Keep in mind all microwave ovens vary in power.

* Do not leave the thermometer in the food while microwaving, unless the thermometer is labeled as safe for microwave use, as this may result in arcing and could be a potential fire hazard.

What do I do if there is popping or arcing in my microwave?

To minimize the possibility of electric shock, unplug this appliance from the power supply before attempting any maintenance or cleaning.

Popping sounds are usually caused by the food item being cooked in the microwave. Food items with a higher fat content will pop and sizzle as they cook. Covering the container will reduce this. Noises can also be heard when cooking foods with tight membranes such as potatoes. Pierce the skin of potatoes before cooking.

Food spills will also cause popping noises. Clean up spills in the microwave as soon as they occur.

Operating the microwave empty may also cause a popping to occur and can damage the interior. Always have something in the microwave when in use.

Using metal or metal-trimmed cooking utensils in the microwave causes arcing in a microwave.

Check to see if the cooking probe has been left in the microwave. If using the probe, make sure it is properly inserted into the food item. If not properly inserted it can cause arcing and destroy the probe.

If using the metal cooking rack, make sure it is firmly in place and not upside down.

If the popping noise is electrical or mechanical in sound, we recommend contacting service.

If the arcing burned a hole through the cavity wall, the damage is non-repairable. You can continue to safely use the microwave if the hole is equal to or smaller than the hole size that you see on the door screen and additional arcing is not occurring during the cooking cycle. If the hole is larger than this, it is recommended that the microwave be replaced.

Should the mica plate inside the cavity be taken off?

No, please do not remove the mica plate. The mica plate is installed on right side of the cavity to prevent the food or oil pass into the wave guide.

My microwave runs but doesn’t heat.

  • Make sure the “Timer” function was not inadvertently used.
  • Check to ensure the door is closed firmly. Close it firmly, but do not slam. This confirms the engagement of the door’s safety mechanisms.

For safety reasons, we offer no do-it-yourself repair advice on microwave ovens due to an internal high voltage capacitor (can hold a high voltage charge even after it has been unplugged). Special equipment is generally needed to make a diagnosis.

If the above suggestions do not solve the problem and the microwave still won’t heat, we recommend contacting service.

The touch control panel on my microwave isn’t working properly.

If the microwave key panel is not responding or working properly, check the following:

  • Make sure that the microwave is plugged into a grounded outlet. It must be a 3-prong outlet.
  • Make sure the clock is set.
  • Check to see if a programming sequence was entered. Sometimes improper programming or a program sequence such as delay start can cause the touch panel to be non-responsive. Unplug microwave or turn off house circuit breaker for 30 seconds. Plug back in, or reset circuit breaker, and try reprogramming unit.
  • Check the house circuit breaker. If the microwave is DEAD and there is no display and nothing works- the problem could be a blown fuse or tripped breaker.
  • If none of these suggestions solve the problem, we recommend contacting service.

My microwave turntable isn’t turning. What do I do?

If the turntable does not turn check the following:

  • Make sure the turntable is centered and seated properly.
  • On models with a stirrer motor there is a shaft protruding up through the floor of the microwave. Make sure the turntable is securely fastened to this shaft.
  • On models that turn on a ring with wheels attached, make sure the turntable is seated securely on the ring.
  • Check the turntable to make sure it is placed right side up. If the turntable plate is upside down it will drag on the floor of the microwave.
  • Check to make sure that there is no food or debris under the “wheels” of the turntable ring. Food can prevent the wheels from moving forward.
  • Be certain you are pressing a cook function rather than a timer function.
  • If the microwave has a turntable on/off feature make sure the turntable was not inadvertently turned off.

If the above suggestions do not solve the issue and the turntable will still not turn, we recommend contacting service.

How can I tell if a dish is microwave-safe?

Follow the directions below to determine if a dish or utensil is microwave safe.

  • Fill a cup with water.
  • Place the cup in the oven on or beside the utensil in question.
  • Microwave for one minute on high.

If the water becomes hot and the dish remains cool, the dish is microwave safe. If the dish heats up, it should not be used for microwaving.

Note: You cannot have one cup of water in the microwave with a power level of 10 for more than two minutes. If you leave it for more than 2 minutes, there is a higher risk of spontaneous boiling.

If both items fit in the oven without placing water on the utensil, the test results will be more apparent. This happens because some heat will be generated downward and the utensil may become warm. This would be a normal condition.

Are there dishes or containers that should not be used in microwave cooking?

For differing reasons, the following should NOT be used in a microwave:

Utensils Remarks
Aluminum foil Shielding only. Small smooth pieces can be used to cover thin parts of meat or poultry to prevent overcooking. Arcing can occur if foil is too close to oven walls. The foil should be at least 1 inch (2.5cm) away from oven walls.
Browning dish Follow manufacturer* instructions. The bottom of browning dish must be at least 3/16 inch (5mm) above the turntable. Incorrect usage may cause the turntable to break.
Dinnerware Microwave-safe only. Follow manufacturer’s instructions. Do not use cracked or chipped dishes.
Glass jars Always remove lid. Use only to heat food until just warm. Most glass jars are not heat resistant and may break.
Glassware Heat-resistant oven glassware only. Make sure there is no metallic trim. Do not use cracked or chipped dishes.
Oven cooking bags Follow manufacturer* instructions. Do not close with metal tie. Make slits to allow steam to escape.
Paper plates and cups Use for short term cooking/warming only. Do not leave oven unattended while cooking.
Paper towels Use to cover food for reheating and absorbing fat. Use with supervision for a short-term cooking only.
Parchment paper Use as a cover to prevent splattering or a wrap for steaming.
Plastic wrap Microwave-safe only. Follow the manufacturer* instructions. Should be labeled “Microwave Safe”. Some plastic containers soften, as the food inside gets hot. “Boiling bags” and tightly closed plastic bags should be slit, pierced or vented as directed by package.
Thermometers Microwave-safe only (meat and candy thermometers).
Wax paper Use as a cover to prevent splattering and retain moisture.

How should microwave ovens be cleaned?

To minimize the possibility of electric shock, unplug the microwave from the power supply before attempting any maintenance or cleaning. Most spills and splatters in the microwave clean up easily with a damp, soapy paper towel or sponge. It is best to clean soil as soon as it appears.

Cleaning Interior:

  • Use a mild dishwashing liquid and damp cloth or paper towel.
  • Baking soda and water may be used on any interior type.
  • Cleaners designed for cleaning interiors of microwave ovens.
  • Heat one cup of water on full power for three minutes. The heat and steam help to soften the food.
  • After the three minutes, allow five additional minutes of stand time.
  • Then, clean as usual. A plastic pad or scrubber can be used.
  • DO NOT use commercial oven cleaners, abrasive cleaners, or cleaners containing ammonia or bleach (which can make the plastic brittle) on any part of the microwave.

Cleaning the door (both interior and exterior): Use only mild, non-abrasive soaps or detergents applied with a sponge or soft cloth.

Cleaning the control panel: Wipe with a soft, damp cloth and dry immediately. Do not spray any solution directly onto the controls

My microwave has an odor.

To minimize the possibility of electric shock, unplug the microwave from the power supply before attempting any maintenance or cleaning.

For “newness” odors in a microwave:

  • First-time usage of a microwave may produce some smoke. This is typically a very small amount and is perfectly normal.
  • An electrical odor in new machines can be normal because the electronic board is “curing” as the circuit board material is heated for first few uses.
  • On microwave/convection models, dust particles can accumulate on the convection element and burn off when in use producing a small amount of smoke. Once dust has been burned off, the smoke will dissipate.

For burned food odors:

  • Clean up spatters and spills as they occur.
  • We recommend washing the interior with baking soda, or a non-abrasive detergent, and letting it dry. We recommend leaving the door open for 2-3 hours when the microwave is not in use to let the microwave “air out.” Some extreme odors like fish or burned popcorn may take several days to wear away.
  • If the odor persists, we recommend you try one of the following: Mix 6 tablespoons of baking soda and one cup of water or mix a solution of 1/2 cup lemon juice and one cup of water. Place either solution in a microwave safe dish of appropriate size and heat for 2 to 3 minutes on high power.