Can you put a pizza box in the oven?
Of all the questions I’ve come across online, this one boggles me most, and I’m shaken to my core by how many blogs say it’s a chill thing to do.
Sure, we can argue about the temperature at which cardboard bursts into flames: The U.S. Naval Weapons Center tested several combustible materials in 1970 and found that cardboard ignites at between 1,000 and 1,380 degrees Fahrenheit without the help of a spark. But cardboard comes in many shapes and sizes, which combust at a diverse (and unpredictable) range of temperatures depending on factors such as thickness and moisture content. After all, cardboard is essentially just glue and however many layers of paper — paper burns at about 480 degrees Fahrenheit. Plus, many pizza boxes contain flammable parchment paper liners to soak up excess grease.
I suspect this temperature debate is why some people seemingly swear by keeping their pizzas — while they’re still in boxes — warm under a low heat in the oven. Though, there are just as many tales online that involve pizza boxes in ovens and apartments smelling like bonfires, kitchens full of smoke or fire departments being called out to college dorms.
On the whole, even if you could successfully reheat a pizza (and its box) in the oven, there’s just no reason to. Pizza pans exist. Tin foil is an option. Putting a slice on a plate and heating it in the microwave is okay. Hell, throw the whole pie on the grill — anything but placing it and its highly flammable box in the oven.
On another note, pizza boxes are doused with PFAS, chemicals associated with all sorts of physiological ailments — including various forms of cancer — and those chemicals can leak into your pie if you heat it while it’s still in the container. Not to mention, your pizza will likely end up tasting like a combination of cardboard and whatever inks the box is decorated with after the reheating process.
Most of all, reheating your pizza in the oven while it’s still in a cardboard box isn’t even a good method. Because the box absorbs most of the heat — and because you won’t be able to see your pizza while it warms up — you’ll likely end up with an over-or-undercooked pie.
In short, don’t fucking do it.