The microwave is one of the best tools for reheating foods, and it's especially useful in the summertime when you might not want to turn on your oven or stove.
On the other hand, have you ever tried to reheat bread in the microwave? It gets sort of chewy and hard, doesn't it? Pizza crust, which is already on the chewy side, becomes downright brittle.
That can happen when you heat it for too long, or using too high a power setting.
Flour consists of protein (called gluten) and starch, and starch in turn is comprised of two sugar molecules. What happens is that one of those sugar molecules melts when it reaches 212°F, which softens it. This is why bread can actually feel soft and fluffy when it first comes out of the microwave. But then when it cools, that molecule recrystalizes and hardens, causing the bread to become chewy and hard.
The Best Way to Reheat Bread and Pizza
So, what can you do?
It depends on what you're trying to reheat. There are things you can do with pizza that might not work for dinner rolls, or that leftover meatball sub.
And let me just say that the best way to reheat bread is to do it in a 350°F oven. If I had a loaf of bread or a bunch of dinner rolls, I'd wrap them in foil first. Same with a leftover meatball sub. Pizza I'd probably heat up on a sheet pan.
But sometimes you don't want to use the oven.
Maybe because it's too hot, or maybe you're already using it for something else. So you have to get creative.
To me, reheating pizza is the easiest. If I only have a slice or two, I'll heat it up on a cast iron skillet. It works great, and retains the crispiness of the bottom crust while melting the cheese and warming up the toppings.
I'll even flip the slice over sometimes to crisp the top, but depending on the toppings, I might not.
Of course, a cast-iron skillet takes a long time to heat up, and it stays hot for a long time afterward. So if the goal is to keep your kitchen as cool as possible, you might not want to use cast iron. And presumably your oven is similarly verboten. In that case, try an electric skillet (if you have one).
A toaster oven is great as well, but you can probably only do a slice at a time.
Reheat Your Pizza in the Microwave
The other thing is that you CAN use the microwave to reheat pizza. You just have to be careful to keep the power low and not leave it in there too long.
Remember, the melting of the sugar molecule happens at 212°F, which is the same temperature at which water boils. So to prevent this, set your microwave to 30 to 40 percent power and heat it for 45 seconds. Check the pizza and repeat as necessary. Your bottom crust won't get crispy, obviously, but the cheese will melt (cheese melts at around 120°F), and the pizza will warm up without the crust becoming brittle.
Reheat Dinner Rolls in the Slow Cooker
What about dinner rolls? Sometimes it makes sense to bake a bunch of dinner rolls and then freeze them.
Or maybe you just have some leftover rolls you want to reheat, or you baked them earlier and want to warm them up. Easy. Wrap the rolls in foil, put them in a slow-cooker with the lid on and heat them on high for about half an hour. They'll be warm and soft when you take them out.
This technique might also work to heat up that leftover meatball sub, although if it's too hot to turn on the oven, maybe it's too hot to eat a meatball sub, too.