can you put cardboard in the microwave

Can You Put Cardboard in the Microwave/Oven?


Frozen food has an essential place in our lives due to our lifestyle. Because it is cheap and takes less time to cook, it is a popular choice for most people. Frozen food is a lifesaver especially if you are a single person. After you spend long hours at work, you may not have the energy to cook something by yourself. Then, you remember the frozen pizza in the freezer and you take it out with its package. When you are ready to heat it, the question comes to your mind: can you put cardboard in the microwave or oven?

We have given the example by using pizza but, there are many types of frozen food that are covered with cardboard. While some of the packages say that it is safe to heat your food with cardboard, some of them don’t. How will you find about the truth then? We will be talking about the situations regarding the oven and the microwave separately because those two have different working mechanisms.

Putting Cardboard in the Microwave

While you use your oven to cook something, the microwave is usually for heating the leftovers. What if you don’t have an oven to cook your frozen food? If you check the signs on your microwave, you will see that it can be set for longer times as well. I have even tried using my microwave to cook souffle in a cup. The most important part is to know how much time will be necessary.

To Defrost Your Food

It will usually take 7~8 minutes for the frozen pizza to cook completely. But, it is always better to check the instructions on the package for the best experience. If your frozen food comes with a cardboard package, you should check if it is microwave-safe. If not, it is best to put it on a microwave-safe dish. You have checked the package and see that there is no sign. What would you do next?

If you are worried that a fire might break out, there is actually no such risk. Microwave’s working mechanism depends on the water molecules inside your food. With the high frequency of those molecules, your food will start heating. Because there is no water in the cardboard, there is no risk of combustion at this point. It will not heat up as quickly as the food itself.

However, we do not suggest you put cardboard in the microwave if you want to defrost your food. Although it is highly impossible to catch fire, it is risky for your health when you microwave your food for 7~8 minutes. There are some chemicals in the structure of the cardboard to make it durable. And these chemicals might leach into your food when you microwave your food for a long time. This could also change the taste of your food in a bad way and you may not enjoy your delicious pizza.

To Reheat Your Food

As for the reheating process, it usually takes around 1~2 minutes for your food to heat completely. The heat won’t affect the cardboard because it doesn’t contain any water molecules. But this doesn’t mean that you can put the cardboard in the microwave. You still need to double-check the microwave-safe sign.

You might see some comments on the internet saying that other people microwaved the cardboard safely. Please keep in mind that each microwave might react to the cardboard differently. If you don’t want a kitchen fire, we suggest you microwave the food without the cardboard.

When you put the leftover inside the microwave, do not forget to place a bowl or a cup of water. Placing water will help you to get soft, nicely cooked food.

Putting Cardboard in the Oven

In contrast to the microwave, the oven can be very dangerous because its mechanism depends on air circulation. Because the cardboard itself could absorb the heat circulated by this air, it could easily catch fire. Depending on your purpose, we will be giving you different options to use the cardboard in the oven.

To Cook Food

Well, the oven’s basic principle is to cook food, right? How about cooking defrosted food that comes with a cardboard package? No matter what you cook, you need to preheat the oven before you put anything in it. The temperature for cooking frozen pizza is around 375~425°F while the cardboard can start a fire around 450°F.

What are you gonna do at this point? There are many cons than pros to put the pizza in the oven with the cardboard. Although the numbers may suggest that you can put the cardboard in the oven, this might be deceptive. Have you ever tried a recipe where the temperature doesn’t match your oven and the food didn’t cook well? This shows that the temperatures may differ depending on the oven itself. To be able to have more control and over your food while cooking it in an oven, you can try using a roaster oven as well. You can check our best roaster oven reviews article to find the one most suitable for you! If you are lazy to find one, we have reviewed Oster Roaster Oven for you on as well!

That fact shows us that we need some alternatives to cook our defrosted food without the cardboard. At this point, let’s think of the pizza as an example again and see some alternatives. For instance, you can use a pizza station, baking tray, or aluminum foil to cook the pizza.

Besides the heat factor, there are other reasons why you shouldn’t put your pizza in the oven with the cardboard. When you put the pizza in the oven with the cardboard, it will take a longer time to heat because the cardboard will be absorbing the heat coming from the bottom part of the oven. Unless the cardboard is not suitable for baking, do not put it in the oven. It will not only lengthen the time for cooking but it will also cause your food to taste weird.

To Heat Your Food

As a combustible material, the cardboard can easily catch fire in the oven. The only way to put cardboard in the oven is when the oven doesn’t work. Or, when you double-check that the cardboard is oven-safe. Otherwise, the next person you call will be a firefighter.

When it comes to the best way to use the oven to heat your food, here are the steps. Heat the oven to the lowest temperature possible and wait for a few minutes for the oven to heat. Then, turn off the power and put the entire box in the oven. In this way, there won’t be a power source to start a fire. Besides, your pizza will heat properly thanks to the cardboard itself. It is a known fact that these cardboards are specifically designed to keep the pizza warm.

Conclusion – Can You Put Cardboard in the Microwave?

Depending on the type of cardboard you use, it is questionable whether you can put it in the oven/microwave or not. When you don’t see the oven-safe or microwave-safe label on the cardboard, it is better not to take a risk and use something else instead. In this article, we have answered the question “Can you put cardboard in the microwave?”

Microwave is safer than oven thanks to its mechanism but you shouldn’t keep the cardboard in the microwave for a long time. As for using the oven, we suggest you refrain from cooking your food with cardboard even if it says oven-safe. You may not know if it is easier for your oven to burn it or not. But, you can put the cardboard only when the oven is not working.

Using non-oven safe cardboard might even change the texture and the taste of your food when it is exposed to too much heat. For the best experience, you can keep the cardboard during reheating your food while you shouldn’t use it for cooking.

If you have any questions or comments, feel free to let us know in the comments.



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