The first is called caramelization, which happens when the sugars in a food become brown. Most foods contain at least some sugar; once foods are between 230 and 320 degrees, their sugars begin to turn brown. Caramel is made from several thousand compounds, making it one of the most complex food products. On a pizza, ingredients like onions and tomatoes become caramelized during baking, making them rich and sweet and flavorful. That brown and crispy crust is also the result of the dough caramelizing.

While the meat and cheese on your pizza also get brown, this is due to a different process called the “Maillard reaction,” which is named after French chemist Louis-Camille Maillard.

The Maillard reaction occurs when the amino acids in high-protein foods like cheese and pepperoni react with the sugars in those foods when heated. Pepperonis that become crispy with curled edges, and cheese that browns and bubbles, are examples of the Maillard reaction at work.

With bread, cheese and tomato sauce as its base, pizza might seem like a simple food.

It isn’t. And now, the next time you’re about to devour a slice, you’ll be able to appreciate all of the elements of pizza that excite our brains, thrill our taste buds and cause our mouths to water.