What makes something crispy on the outside?

Something becomes crispy on the outside when it loses water quickly and gets hot at the same time.

Imagine you're baking a cookie in the oven. The outside of the cookie is close to the hot air, so it starts getting warm really fast. As it warms up, the water inside it turns into steam and tries to escape, like when you see little bubbles on top of soup as it heats up.

But if the outside is too dry, that steam can’t escape easily. It gets trapped, and the heat makes the outside get even drier and harder. That’s why your cookie becomes crispy!

• Heat helps things become crispy by drying them out.
• Water inside food turns into steam when it gets hot, and if it can’t escape, the outside gets even drier!
• The more dry and hot something is on the outside, the more crispy it becomes.

Just like your favorite crispbread or a toasted bagel, they all become crispy because of this little dance between heat and water!