Why does day old delivery pizza get hard?!

Why does day old delivery pizza get hard?

Our family usually doesn't always eat a whole pie of pizza and we leave it in the oven. If I eat it the next day the crust and pizza is harder when cold or when heated up again. Why is this? Can you please give my a detailed answer.

12 hours ago
Great answers guys. I don't mind the pizza getting hard I was just wondering. I didn't realize it could of been bad for me.

The reason food dries out is because of the air circulating around it....so when you leave the pizza in the oven for hours it changes it's texture.....If I were you as soon as you are finished with the pizza and have leftovers...wrap it in aluminum foil and refrigerate it.....then when you want to eat it again...preheat the oven and place it in the oven for about 15 minutes...all closed up..then open it and heat for about 10 more minutes or less depending on how thick it is......that way it is heated inside and toasty outside...if you heat the oven to 350 it will heat without burning....it might take you a couple times to get the timing right...good luck..also don't leave food out ..always wrap your food and put in refrig. to prevent food poisoning. especially in the hot summer....take care.
Mama Jazzy Geri