Understanding What Makes Popcorn Pop

Popcorn is a low-calorie treat that is enjoyed by millions of people. It is so popular that it has been a mainstay of movie theaters for over a half century. It is a puzzle to quite a few individuals, though, what makes popcorn pop.

Explaining and understanding popcorn

It is quite simple to explain why popcorn pops, but understanding it takes a little bit more effort. We say that popcorn pops because when it is heated, steam inside the kernel causes it to burst and expand. While this is what happens, it doesn’t actually explain why or how.

History of corn

There is a debate on the exact origin of corn, but it originated either in Mexico or South America. The ancestor was almost certainly wild maize. It needs to be mentioned here that although many people use the terms “maize” and “corn” interchangeably, these are not the same thing.

The corn used today was bred to have the desirable traits for what it was going to be used for. In the process, a number of types of corn were created.

Types of corn

Corn is most often divided into dent, sweet, flint, flour, pod, and pop corns. Popcorn is actually a kind of flint corn, while sweet corn is actually a type of dent, though.

Thus, flour corn is obviously used to make flour. Dent is the corn on the cob and kernel corn people eat. It is also the type that is fed to livestock and other animals. Pod corn is ornamental and rarely eaten. That leaves us with flint corn.

Popcorn and other kinds of flint corn have a hard, normally thick shell surrounding each kernel, particularly when it is dried. At the center of the kernel is a small amount of starch. The hard shell prevents moisture from evaporating as easily as with other corn, even when it is dried.

It is the combination of the hard, thick hull and the moisture content that is responsible for popcorn popping. When dried popcorn is heated, the relatively high moisture inside of the kernel expands as it turns to steam.

However, the hull also prevents the steam from escaping. Finally, enough pressure builds up in the kernel to overcome the resistance of the hull and it bursts. The sudden release of pressure allows the starchy heart to expand.

Since other corn also has a hull, it will also pop, but the hulls burst more easily, so they don’t expand nearly as much. In fact, other grains, like rice, will also pop. The reason is the same. It is the same reason that a thick-skinned potato will burst if it is microwaved without cutting through the skin to allow the steam to escape.

The expansion of popcorn is enormous. Three tablespoons of popcorn kernels are capable of producing six cups of popped popcorn. That is a volume increase of over 25 times.

Using this knowledge

If sufficient time lapses, dry popcorn kernels will lose moisture. The result is that fewer kernels pop and the popped corn doesn’t have as great a volume as it should have. If this happens to you, don’t despair.

Just put the popcorn in a bag and put it in the freezer. Despite the cold temperature, there is usually a lot of moisture in the freezer. The kernels of popcorn absorb the moisture and if left overnight, should pop like they would if they hadn’t dried out too much.

As you can see, while it might seem that knowing why popcorn pops is trivial, the knowledge has an actual application. This is the way that knowledge works and why it is exceptionally valuable.