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Can You Microwave Stainless Steel? (Microwave Safety Tips)

Stacked stainless steel disc

Stainless steel is one of those metallic materials that has always been designated as “microwave-unsafe”. And that’s a bummer considering most of our kitchen utensils and cookware are made of stainless steel.

If you’re wondering why that is, it’s because this iron and chromium alloy happens to offer a high degree of resistance to corrosion and rusting. In addition, compared to other materials, it’s relatively more durable, easier to clean, and non-stick.

Unfortunately, when it comes to microwaves, they reflect the radiation instead of absorbing it. And if the material is left in there long enough, it will eventually generate sparks that could morph into an uncontrollable fire.

We’ll explain what exactly happens when you microwave stainless steel after discussing its composition. So, keep reading if you’d like to learn more.

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What’s The Composition of Stainless Steel?

Stainless steel is an alloy (mixture) of chromium and iron. However, the material is usually classified into different grades. The grades are determined by the ratio of the ingredients and the type of components used in production. For example, if the chromium used accounts for less than 10% of the total composition, the final product will certainly fall into the low-grade category.

The other types of components used in production include nickel, copper, molybdenum, silicon, carbon, sulfur, manganese, and nitrogen. They are sometimes added during the alloying process to improve the corrosion resistance, weldability, magnetism, formability, or strength.

Stainless steel forks
Image By: Foundry Co, Pixabay

How Can You Tell if Your Kitchenware Is Made of Stainless Steel?

Just look for some sort of marking or stamp at the bottom of the cookware or on the side. You’ll most likely find something that describes the material used because most producers like to provide their potential customers with as much information as they can, to help them make an informed decision before making a purchase.

That being said, if you don’t find any visible marking or stamp, the responsible thing to do is to assume it’s not microwaveable. Or you could test it in one of the following ways:

  • Look for a sharp object and try to make a scratch on the surface. If you succeed, it’s definitely not stainless steel.
  • Use a magnet to find out whether or not it is ferromagnetic. Stainless steel is a non-magnetic allotrope of iron. Scientifically known as austenite.
  • Expose it to intense heat, to see if it changes or loses color. If there are any observable changes, your kitchenware isn’t made of stainless steel.

Are All Stainless-Steel Products Microwave Unsafe?

No, not all of them. To make stainless steel microwavable, you could mix it with elements such as aluminum during the alloying process. Of course, the aluminum will be weakened after losing most of its electrons to the steel, but that doesn’t matter as you’ll have managed to produce a product that’s microwave safe.

Even if your stainless-steel cookware sets are microwave-safe, you still have to be cautious while heating your food. The following tips might come in handy:

  • Don’t leave the stainless-steel container in the microwave unattended. You have to keep a close eye on it, as it only takes a couple of seconds for things to go wrong.
  • Set a timer. If you heat the container for too long, it might generate sparks that could burn the whole house down.
  • The edges of the container should be as far away as possible from the microwave walls. If they come into contact, they’ll generate sparks.
  • Ensure the container’s surface is evenly covered by the food being heated. This reduces the surface area that’s exposed to microwave radiation.

What Happens If You Try to Heat Up Food in An Un-Microwaveable Stainless-Steel Container?

First off, the radiation generated by the microwave will be reflected by the surface. This is a hazardous process, as it involves the extraction of electrons from the stainless-steel container, which ultimately creates a thin metal layer. You should definitely worry about that layer because it has great potential for not only burning the appliance but the whole house as well.

Secondly, there’s a high likelihood that the metal will contaminate the food in the container. Just so you know, people who have been chronically exposed to chromium often grapple with kidney and liver conditions. Even if the levels are not high enough to affect you, the electron movements could still change the food’s taste.

stainless steel straw in a clear glass
Image By: Michelle Patrick, Shutterstock

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Frequently Asked Questions (FAQs)

Does Microwave Radiation Cause Cancer?

No, studies have proven that the radiation produced in the microwave doesn’t have the potential to cause cancer. Just like visible light and radio waves, this type of radiation is considered non-ionizing. From our understanding, ultraviolet light is the only form of non-ionizing radiation that’s harmful to humans.

Then again that doesn’t mean that microwave radiation is completely harmless. Scientists say it usually heats up body tissue the same way it does food. Meaning, if you expose yourself to it for an extended period of time, you’ll be burned.

How Does a Microwave Generate Radiation?

It relies on an electron tube that’s commonly known as the magnetron. Once the radiation has been produced, it will be absorbed by the food, causing its water molecules to vibrate. That vibration is the reaction that results in the generation of the heat used to cook up the food.

If you’d like to reduce your cooking time, add more water to your food. The appliance will have more molecules to play with, consequently generating more heat.

Is 304 Stainless Steel Microwaveable?

We like to call it the “18/8 stainless steel” because it contains at least 8% nickel and 18% chromium. Most consumers find the 304 stainless steel aesthetically appealing, so it’s not just about its exceptional resistance to corrosion and high melting point.

Sadly though, this isn’t the type of material that you’d want anywhere near your food. Nickel, just like mercury, is considered carcinogenic.

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We’d advise you to steer clear of stainless steel while shopping for cookware to be used in the microwave. Such products are only meant to store or handle food, and not to microwave them. Those that are designed to be used in a microwave usually have a symbol, stamp, or marking at the bottom of the container.

Featured Image Credit: HelloRF Zcool, Shutterstock


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