Whether it’s melted on a pizza, between slices of bread, cut into squares on crackers, or packed as single-serving sticks, Americans love cheese! Each person in the U.S. eats about 40 pounds of the dairy product per year. And they have more than 2,000 varieties of cheese to choose from!
Humans have enjoyed cheese for thousands of years. It was likely first made as a way to preserve milk, which spoiled easily and was difficult to store. Cheese is made when milk proteins called caseins are turned into a solid. These proteins are separated out as curds, while the remaining liquid part of the milk is discarded as whey. Then the curds are pressed into wheels or other shapes to mature or age.
The amount of moisture lost as cheese ages and the way it is first pressed determines whether a cheese is soft, like a brie, or hard, like a Parmesan. Mold matters too. Certain types of cheeses can be made only by exposing the maturing cheese to specific strains of mold.
When it comes to melting, experts say the more moisture the better. Cheese is a mixture of dairy fat, proteins, and water. It gets its structure from its clumped-up proteins. As it melts, the proteins in the cheese break apart, giving the cheese a meltier form. The water in the cheese helps hold the fats and protein clumps together, resulting in a stretchy, gooey cheesy dish.