April 29

What is Microwave Safe Bowl? – Useful Guide


Author: Cornelia Suehr
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Most people consider a microwave-safe bowl as a type of container or bowl that will not get damaged when used in a microwave oven.

That is a bowl that will not break, chip, crack, or be strained as a result of use in the microwave oven. However, breaking an unsafe bowl is the least of your concern.

Some bowls like iron may emit a harmful substance that can cause damage to the body. With aluminum or steel utensils the entire oven might also be damaged as a result.

Another example is plastic. Most people highly recommend not using certain kinds of plastic, like Styrofoam, in the microwave oven mainly because of the harmful agents it can emit into the food.

It is thus important to know what is microwave safe bowl so you don’t get your food, microwave, or the bowl damaged.

When you use a microwave, the whole container does not get hot, heat is passed through the bowl by radiation into the food that is being prepared.

Basically, a microwave-safe bowl is a utensil that has been tested and approved to be used in a microwave oven.

As a rule of thumb, only heat absorbent bowls are recommended for use in the microwave oven. The materials used for microwave-safe bowls are ceramic, wax, paper towels, parchment paper, plates or napkins, glassware and certain microwave safe plastic e.t.c.

To check for microwave-safe bowls look for a symbol with three wavy lines. More on this below

Also Read: How to tell if plastic is microwave safe?

Why is it Important to Use a Microwave Safe Bowl

Microwave safe bowls
If the bowl is not microwave-safe it can be very dangerous for the food and yourself. Source: MasterChef

When you buy a new microwave oven, its guide will probably recommend the type of container you can use in it. Microwave ovens are much more flexible than conventional ovens because you can use a variety of bowl types.

One of the major reasons why it is important to use a microwave-safe bowl in a microwave oven is because of the heat the oven emits, it is transferred through the bowl directly to the food such that the bowl might not be hot but the food will be.

Other reasons include not wanting to damage the bowl, your microwave oven, or even your food. Some bowl materials find it a little difficult for heat to penetrate, therefore the purpose of microwaving may be defeated and you don’t want that.

Read more: Best 1100 Watt Microwave Ovens

What is Microwave Safe Bowl?

Microwave Safe Symbol
You can find a bowl with this symbol for microwaves. Source: Reviewed

For a while, most people found it comfortable to use basically any type of bowl or container in their microwave oven and while this might have ended up doing the job at one time or the other, they could have used better microwaving bowls/containers.

1. Look For Microwave-Safe Symbol

Most brands that make kitchen utensils, appliances, and kitchenware have made things much easier by using the sign or symbol used for identifying silverware that is safe to use in your microwave oven.

When you want to buy a microwave bowl, simply check the sides, if you see three wavy lines, it means it is perfectly safe to use in the microwave oven.

If it does not have this symbol, there is a probability that it is also safe for a microwave oven but looking for this sign/symbol makes things much easier for most people.

Some other brands choose to write the phrase “microwave safe” on their wares as opposed to the sign, either of these signifies that it is safe for use.

2. Plastic Recycling Codes

Plastic containers, on the other hand, are not as good for microwaving food. Plastics are not made equally and some are highly dangerous in microwaves.

When using plastic, if it does not specifically mention “micrwoave-safe” take note of its recycling code. The recycling code rangers from 1-7 with 5 being the best for microwave ovens.

plastic recycling number
Plastic Recycling Numbers. 5 is the best. Source: Eartheasy

Read more: How Much Radiation Does a Microwave Oven Emit

3. Ceramic, Glass and Other Materials – Recommended

The major type of materials used for making the most microwave-safe bowls include bowls made out of ceramic, wax, paper towels, paper plates or napkins, glassware e.t.c are all considered safe.

Ceramic and Glass is not just safe, it is highly recommended.

4. Metals

Metals like stainless steel, iron, copper, brass and aluminum should absolutely be avoided.

These metals reflect the microwave radiation and thus are actually a fire hazard.

In short, avoid using metallic bowls.

How to Test if a Bowl is Safe for the Microwave

What is microwave safe bowl
Don’t use plastic as it is not recommended. Only certain kinds of plastic are safe.

There’s really no foolproof method of testing for a microwave-safe bowl, so to avoid all the hassles, you can simply get a bowl with the microwave-safe sign/phrase.

If you don’t have one and want to do a quick test for the one you already have at home. Simply fill the bowl with water and put in the microwave oven, switch it on to the highest temperature and leave for 1-2 minutes.

Finally, open it and put a finger in to test for the temperature of the water, make sure it’s not too steamy to avoid burning yourself.

For this test, the bowl should be cold and the water hot, if the bowl is hot and you’re sure the heat isn’t from the hot water in the bowl, its probably a sign that the bowl is not microwave oven safe.

Dangers of Using a Bowl that Is not Microwave Safe

So many things can happen as a result of using a container that is not microwave-safe in your oven and these dangers can be avoided as they are quite predictable if you’re violating the rules of a microwave oven. Nothing good is likely to come from that.

Some of the dangers and downsides of using a bowl or container that isn’t microwave-safe are:

1. Uneven Cooking

The food might not microwave evenly: anyone who has tried this at one time or the other in their lives can testify that your food might just come out warm on one side and very cold on the other.

If the purpose of microwaving your food is to kill pathogens, then that will not be possible, because the level of heat in the microwave will not be even throughout your food

2. Personal Risk

Your hand might get burnt: yes literally, if you are using a bowl that you’re not sure is microwave safe, then it is recommended that you use an oven glove at all times, both to put food in and to take it out.

A microwave oven is designed to only heat the food and not the bowl, but a bad oven bowl might heat with the food and you might just get your hand burnt.

Plus, using certain plastics in microwave is a cancer risk.

Also Read: Is Plastic a Threat To Your Health (Harvard)

3. Damage to the Appliance

The bowl might melt; some microwave ovens will tell you never to put certain plastic in, if you make this mistake with the wrong oven, it might melt the bowl.

Plus using certain metal utensils is even a fire hazard.

There are a lot of downsides to not following the rules and upsides, if any, are very few. Microwave-safe bowls are very important for use, to avoid damage to both your food and your appliance, try to stay away from plastic in your microwave oven.


A microwave-safe bowl is really important since microwave has become an everyday necessity.

To make sure you don’t get in trouble due to usage of the wrong container follow the guidelines given here to know what is microwave safe bowl.

About the author

Cornelia Suehr

A professional chef and a passionate writer on all topics related to cooking, baking, appliances and kitchenware. Her posts resonate with foodies, home chefs and professionals.


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