Can You Microwave Cardboard

One of the most common kitchen gadgets, almost a must-have, is the microwave. It’s safe to say that almost every house in the urban setting has a microwave. We live in a fast-paced world, and it’s only natural that we would like to warm or reheat our foods fast.

So with all this love for this gadget, there come rules on how you should operate it. Since we want to go to the restaurant; buy different foods, the oven is excellent to make sure you eat it warm. Sometimes you will have the stores cover the food in plastic containers, but other times in cardboard. While you may want to set any container in the microwave, this is not as safe.

So the article here seeks to find out whether it’s safe to use the cardboards in the microwave or not.

Not so first, though!

What cardboard are we talking about?

This is more like paperboard and while you may think you know it all too well, let’s dig deep. You can comfortably use it in shipping and packing too. Cardboard is more of a heavy paper product. It’s, in fact, one of the thickest papers. You can usually use it for the packaging and the shipping of the foodstuffs.

You can also have corrugated cardboard. Such a feature means you have two flat cardboards, and they always also have grooved middle sections. If you are going to buy the six-pack beverage cans, then you will have such cardboards.

Suppose you will cook the food on the cardboard though you will have to consider a few factors. This is true when you’re talking about the cardboards that aren’t made for use with your food.

Some of this cardboard will have a chemical layer that most likely contaminates the food. For that matter, you have to consider and know that no, you can’t cook with them in the microwave.

Do you know the different types of cardboards we have?

Of course, like any other utensil, you will have different types of cardboards in the market. Let me list them here just in case you may have already seen some of them here before.

  • Eco-friendly food package
  • The sectioned food trays
  • Pizza boxes
  • The take out containers
  • The disposable cups

I should also mention that the microwave does come with cardboard to protect the waves section.


Can you microwave the cardboard?

From the surface value, it looks not like a very great idea. Generally, it’s okay to use the paper plates in the microwave and the cardboards in the microwave. So then you will use it efficiently and without any issues.

I know why you think it’s unsafe. Of course, the papers and the cardboard will also help to start a fire quickly. Note that the microwave works also means that the cardboard is generally safe to use in the microwave.

How the microwave works

Generally, when you set the microwave food, it will heat the liquids in it, which will help heat the food efficiently. When this happens, you will have the liquid move through the food, thus heating it efficiently. Remember, the food moisture is the result of rapid heating.

Be informed, therefore, that the cardboard, though, never has a lot of moisture. As such, it will start to heat up faster. It will eventually warm up but not as much as the food does. This is why it remains a safe option to set in the microwave.

I know you may say it will take on the temperature of the food. Of course, it will, but then it will not reach such a high temperature to reach the burning or combustion level.

Regardless I have to say again, just like we had mentioned already, not all types of cardboards are safe to use.

So then, how is the microwave going to heat your cardboard?

I know one thing is true for you to understand how this great gadget works, you have to know precisely what is in it. Cardboards often work perfectly by generating the microwaves, thus its name.

So these microwaves are also what we refer to as electromagnetic waves. It has the wavelengths that are between the infrared radiation and the radio waves. The magnetron inside the oven can then generate a high frequency of 2450Mhz.

So then, as discussed earlier already, the microwave will heat your food differently. It will often absorb the water, fat, and sugar molecules. This then is what they will begin to rotate, creating a molecular dance and heating the food fast.

Remember, you aren’t supposed to set the plastic in the microwave just because some of the plastics actually will attract the microwaves still.

Heres how it works with the cardboard though

By now, you know there are different styles of cardboards you will use. And it’s safe to say that sometimes you can use it in the microwave.

Such microwave-safe cardboards then make using Cellulose or what we refer to as wood fiber. Generally, the cardboard then has a moisture content of about 9-12%. As it goes on heating, you will notice one thing that the cardboard will keep on reducing moisture.

In most cases, it will go to reduce the moisture by up to 1%. And if you then keep heating it, then it becomes combustible. It’s worth mentioning that this rarely happens because it takes you such a short time to heat the food. Regardless of whether you will use the cardboard, you have to factor in the oven surface area and the likes.

If you are going to use the cardboard, you what to be all-around checking because everything could happen too first for you. Generally, this is the reason why I’m cautious about using the cardboard since when it dries up, then it will become an igniter. Just know that when you are using the cardboard, then that it’s an explosive choice.

So the primary question,

Can I microwave the cardboard that is made using the food and drink?

Well, we already said you could use some cardboard. However, it’s not a good idea because you don’t know when the cardboard is too dry that it becomes combustible. I know sometimes you don’t want to dirty your plates. Are you tired from a busy day’s work? You may want to heat the pizza in the cardboard, but is it okay?

If you’re going to use the cardboard they make using the wood fiber only, it’s a great choice. Just make sure you don’t use any additional ingredients, and as such, you’re safe to use it.

Also, it will only become a problem when it absorbs the food or liquid in. The way it then works is that the microwave absorbs the moisture from the food. In most cases, by the time you finish reheating, the cardboard will still be safe.

Can I reheat the food in the same cardboard I already used in the microwave?

It’s not a good idea just because the moisture level is already down, and that will also mean you risk drying the cardboard thoroughly, thus making it combustible.

Is the food-grade cardboards heat resistant?

I know the only thing that will make you want to use the microwave oven cardboard is if they are heat resistant. An item is only heat resistant if it can stand up to a temperature of 140°C. The item is also fire resistant if it can stand the temperature of up to 250°C.

In most cases, your cardboard is safe if it doesn’t reach a high temperature of 427°C. So here you’re talking of the simple cardboard box that comes with your pizza. For that case, there’s a lot to consider. These boxes are supposed to carry the pizza home, not really for you to use them for any cooking.

Regardless they have the following features.

  • They are durable, and as such, you can use them as you are stacking.
  • They have a heat resistance of up to 80°C.
  • It will also retain the warm temperature.
  • It’s meant to make sure your crispy food doesn’t get soggy.

In general, if you have to use the box, then you will need to do it cautiously.

Can I use all the cardboard then in the microwave?

Of course, some of the boxes will stand the high heat, but this doesn’t mean all of them are safe to use in the oven.

If you are thinking about the pizza boxes, I should mention that not all boxes are safe to use. Some of them have metal clasps or aluminum foil on the inside and what that then means is that you shouldn’t use it in the oven.

So before you set it in the oven, you will need to read the manufacturer’s comments. That will guide you to knowing whether it’s safe to use. Some of the brands will then tell you whether the box is safe to use in the oven. If they didn’t say that it’s safe to use, you shouldn’t use it in the microwave for safety purposes.

Remember only to use the cardboard in the microwave for shorter periods. You see, over time, it will be flammable when left in for long. Even when they indicate that it’s safe, remember it’s only safe for shorter periods.

Your cardboard boxes then make using the recycled materials, which can only mean that they will have some metals or contents like plastic, which is not microwaved safely.

When the cardboard is made of metals in other parts, then you shouldn’t set it in the microwave at any time. So then you should check the label on the container. Some of the companies will tell you if the cardboard has metals.

If your cardboards have wax or paint, then you shouldn’t set them in the microwave as this will melt. When that happens, then it either becomes flammable or even contaminates your food. Glue is horrible as it will release toxic flames.

If you are going to use the card box in the microwave, you should do the following.

I know the main reason you want to use the card box is that you don’t want to dirty your plates. So if you are going to use the method, you should check out the following points.

Don’t place the empty pizza box into a microwave. This will make it explosive, and it will cause a fire. You see, when it has the food on, then the microwave absorbs the moisture first.

Confirm first that your box doesn’t have any metal parts, glues, or anything like that. This will be hazardous to your microwave.

Also, make sure it doesn’t have glue, plastic, or even wax as all of that then is toxic to your microwave.

Don’t let the cardboard reheat your foodstuffs over a long time. When you do this, you allow it to lose all the moisture it has then, making room for it being a flammable object.

Which is the safest option?

I’m not one to support the whole process of using the cardboard in the microwave. You are better of using the following.

Choose the cans that use glass.

If you are using the tempered or heat-safe glass, it remains the safest choice to use. But you should remember that if you’re going to reheat the food for a long, the glass will get too hot. That is what can be damaging.

Ceramic containers

If you have great ceramic containers, you are good to go. Use them to reheat your food just because they remain the safer choice to use. Just make sure that the ones you use don’t have a lot of lead and arsenic in them.

But don’t you ever put your food in a container or cardboard with aluminum foil. The foil will develop a hot pocket, and then it goes on to cause fire ignition.

So whats my final say?

Well, if you look at it all, you shouldn’t use cardboard. It’s much safer for you to use a microwave-safe plate than cardboard. The problem with the cardboard is that you aren’t just sure when it will cause that fire.

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