Pizza will get cold. It needs to be refrigerated, and when it is time to eat more of it, it needs to be reheated. The question today is: Can it be reheated in its own box? Can a pizza box survive the environment of the oven?
Can you put a pizza box in the oven? No. A pizza box is made of cardboard, which will burn at around 285 degrees Fahrenheit, and will ignite at around 420 degrees Fahrenheit. Naturally, this does mean that the pizza box can technically survive sitting in the oven if you set it to 250 degrees. But given enough time, it will burn even then.
The idea behind putting a whole pizza box in the oven is that sometimes you have more leftovers than you have finished pizza. Given that situation, you might be tempted to try and reheat the whole pizza at once. But this never works, no matter how cleverly you might control the heat.
This is due to the way heat works. Heat is the activity of molecules in a body. The more activity, the hotter that body is (extrapolate whatever metaphor you want from that). A body is either going to be in a state where heat is increasing or decreasing. If there is nothing to slow down its heating, then it will only get hotter.
This means that while an oven might be set to 250 degrees Fahrenheit, the pizza box you place inside can heat well past that temperature. Suddenly, you go from cutting it close in order to be clever, to having to pull a fire extinguisher out in your own kitchen to keep your pizza box from killing you.
An Alternative Method
There are two goals one is usually trying to accomplish by sticking a cardboard pizza box in the oven. The first is finding a low-maintenance solution to a storage problem. The second is reheating the pizza.
Unlike the initial act of trying to cook cardboard, neither of these is a bad problem to solve. It just requires that you solve it properly. Luckily, there are alternative methods to solving both of them that do not obligate you to call the fire department afterwards.
The first and best one is to both store and reheat the pizza in aluminum foil. In truth, you only really need to reheat the pizza in aluminum foil. Storing it in aluminum foil means not having to wrap it later, but of course, wrapping it later means you do not have to take an extra step to store it.
This organization of labor is very important for especially lazy people who dislike taking action they do not need to until they absolutely have to. No judgment is being weighed against that kind of person. This is simply an acknowledgement of such a person’s existence for the benefit of the reader who does not understand them.
Aluminum foil is great for reheating because aluminum foil is especially good at conducting heat.
Every material in existence has a property called “conductivity”. Conductivity is the material’s ability to convey energy through itself. Imagine you are trying to get electricity from one end of the room to another. Rubber would not be able to transfer that electricity. Metal would do so the best.
Metal is more conductive than basically any other material. Aluminum foil is included among those metals, even though it is so thin it might not seem like a metal at first blush. Metal can contain and pass on more heat than your average material. This is what makes it so great for reheating things all the way through.
Just be careful that you never ever try to reheat pizza wrapped in aluminum foil using a microwave. You can take the pizza out and microwave it, but aluminum foil should not ever be allowed in a microwave. Ever. It will catch fire not only faster, but far, far hotter than cardboard does.
In Conclusion
Putting a pizza box in the oven is generally a bad idea. Maybe it fits, maybe it does not even burn immediately, but if you try to reheat your pizza that way, you will start a fire. So, stay safe, and use aluminum foil.
Just don’t use it in a microwave. Ever.