Top 10 Things Of What Not Put In A Microwave

Tara Williams

Food Writer & Editor For KitchenSanity

Tara Williams is a seasoned food writer and editor who's been with KitchenSanity since its beginning. With a knack for experimenting with food and creating delicious recipes, she's your go-to for straightforward kitchen advice and practical tips from personal experiences. As a mom of two, Tara understands the value of time. She crafts articles that enhance your cooking skills and free up time for what matters most—like family moments.

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Microwaves operate using oscillating electromagnetic energy. It sounds complex, but to put it simply, microwaves are similar to radio waves, but move back and forth at much greater speed. They work by causing the molecules in your food or drink to vibrate and heat.

Handy for fast and efficient heating and cooking, the microwave oven is a go-to for busy people wanting to save time. As wonderful and versatile as this appliance is, there are certain things it can’t handle.

A popular question that we’ve been asked is, can you microwave eggs? We left out eggs out of this list because it is possible to create fantastic dishes with care and caution.

So here’s our guide to 10 things you should not put inside your microwave oven.

1. Frozen Meat

defrost frozen meat in microwave

Depending on the model, some small microwaves have a rotating plate and some don’t. If your oven doesn’t, this can lead to uneven distribution of heat, resulting in lopsided thawing and cooking.

Not only that, defrosting meat in a microwave usually takes a long time.

As a matter of fact, the edges of the meat will start to cook and turn brown, while the inside remains fully frozen. This is because microwaves cook from the outside in, and can only penetrate a maximum of 1-1 ½ inches into any food.

Another problem is that when meat heats from between 40 to 140F, the rate that bacteria grows is significantly increased.

2. Styrofoam

microwave Styrofoam takeout box

There are two different versions of what we consider to be “Styrofoam.”

One variation of this is in fact a form of plastic, therefore may contain nasty chemicals that will leech into your food and cause health problems over time.

The other type has different ingredients which can withstand heat more effectively and can be safely microwaved.

Can you microwave Styrofoam? Your best bet is to check underneath or on the sides of the container for a label. Microwave safe Styrofoam will be clearly labeled. If you’re unsure, give it a miss.

3. Metal

Can you put metal in a microwave? Putting metal inside a microwave has always been seen as a major hazard. It can cause sparking, plasma discharges, or even fires.

While there is new evidence to suggest that some types of metal may be safe to put inside, we don’t see a real reason to do it.

Although you won’t blow up your house, you may short out the electrics of the microwave oven, rendering it useless.

Related | Can You Microwave Aluminum Foil?

4. Plastic Containers And Plastic Wrap

plastic container in microwave

The rule of thumb is to avoid microwaving anything with any form of plastic in or around it. The logic behind this is that when plastic is microwaved, you run the risk of creating carcinogens, although this is still highly debated.

Heating plastic has, however, been known to release harmful and toxic chemicals such as toluene, benzene, xylene, PET (polyethylene terephthalate) and BPA. These are chemicals which can easily compromise your health.

There are companies now with BPA-free plastic and “microwave safe” plastic dishes, such as Tervis Tumbler, but more research is needed into how safe these materials actually are.

Plastic wrap should be avoided as it will melt, as will the average plastic bag.

5. Water

Surprised? Microwaving water is one of the top ways to get scalded.

The problem is that when water is microwaved, it super heats. This means that it won’t look hot when it’s at boiling temperatures and beyond. In fact, it will look almost as if you poured a cold glass of water and set it in the microwave.

This becomes especially important if you are cleaning your microwave using the water method with lemon or vinegar. Check out our post on using this method in How To Clean A Microwave.

The dangerous part? There is a lot of energy stored inside that water after it has been microwaved. Once you stir it or add a tea bag, it can disrupt the latent energy and you could be faced with water exploding out like Mount St. Helens.

6. Lunch Bags

Whether the bag is manufactured with plastic, paper or cloth, it should be kept out of the microwave.

Apart from igniting and causing a fire, most of these lunch bags are not clean on the inner sides that you can’t get easy access to.

Depending on where it was manufactured, there may be lingering chemicals that are emitted when heated. It’s a bit shocking to think that these are the vessels we are storing food in every day.

7. Bread

While putting bread in the microwave isn’t going to cause a nuclear meltdown, it will cause your bread to dry out and become tough.

In fact, it can become rock solid the longer that you leave it in there. The problem is that the microwave effectively dehydrates your bread until there is no moisture left.

If heated for too long, the microwaves may end up looking for somewhere else to go – such as back into the magnetron which operates the entire oven.

What is the solution to microwaving bread effectively? Add lots of butter!

8. Fruits

Many fruits will break down very quickly when cooking in a microwave.

Fruits such as grapes are likely to explode, whereas even the humble raisin can create a plasma discharge strong enough to ruin the microwave!

It is also worth mentioning that fruits and vegetables tend to lose a lot of their nutritional value when cooked.

9. Hot Peppers

When it comes to hot peppers, your microwave will be safe but you might not be!

When hot peppers are heated, capsaicin – the active ingredient which makes peppers spicy – can be vaporized into the air. When you open the microwave door to remove the hot peppers, the spicy mixture of steam and air exiting will have your eyes streaming.

10. Nothing? Yep, Nothing!

empty microwave

So, to get a bit technical on you, microwaves are produced by a magnetron – obviously, the most important component of your oven. These special waves cause the molecules in food to vibrate rapidly, turning the resulting friction into heat.

Those microwaves need to go somewhere. If there’s no food or water molecules for them to act upon, they will end up targeting straight back into the magnetron – which can make it malfunction or blow completely.

The same thing applies for putting items in your microwave that have little to no moisture.

Written By Tara Williams

Tara Williams is a seasoned food writer and editor who's been with KitchenSanity since its beginning. With a knack for experimenting with food and creating delicious recipes, she's your go-to for straightforward kitchen advice and practical tips from personal experiences. As a mom of two, Tara understands the value of time. She crafts articles that enhance your cooking skills and free up time for what matters most—like family moments.

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