Why does Popcorn Pop?

Malcolm Tatum

Popcorn is easily one of the oldest and most recognizable of all snack foods. Known to some of the earliest known civilizations of the New World, the concept of popping corn for a treat is now common around the world. The corn pops because of moisture inside the kernel.

A heaping bowl of popped popcorn.
A heaping bowl of popped popcorn.

One of the first things to understand about popping corn is that every dried kernel retains a small amount of moisture. This is essential to ensure that the popping process can take place. By applying a heating agent, the moisture expands and forces the interior of the kernel to burst through the hull. At the same time, the combination of heat and moisture cause the fluffy white texture that defines the treat.

The stages of popcorn popping, starting with a seed and ending with a kernel of ready-to-eat popcorn.
The stages of popcorn popping, starting with a seed and ending with a kernel of ready-to-eat popcorn.

Several different methods have been employed in the making of popcorn. Combining the flint corn kernels in a metal container with a small amount of oil is one of the oldest methods. The container would be sealed with a lid, to prevent the popping corn from flying out of the container. By holding the container over an open fire and gently shaking the contents, the temperature gradually rises to the correct level and the kernels begin to pop open.

Air poppers produce a steady stream of hot air that causes the popping action.
Air poppers produce a steady stream of hot air that causes the popping action.

Along with using an open fire, it is also possible to make use of a range top, and the same principles apply. Oil and dried kernels are placed into a metal pan, covered with a lid, and then gently shaken over the gas flame or the electric eye. In a short period of time, the popcorn begins to pop. Adding a little butter and seasoning makes a great snack.

Salt, which is often used to top popcorn.
Salt, which is often used to top popcorn.

During the middle of the 20th century, electric corn poppers became very popular. Many of these models involved a base with an electric heating element, and a clear plastic body. Oil and popcorn were placed in the bowl of the heating unit, then covered with the tall clear body. This made it possible to watch as the corn began to pop and fill the body. Once all the kernels were popped, the device was turned off and the plastic body flipped over to act as a bowl for the freshly popped corn.

Hot air poppers came into vogue during the 1970s. The idea behind this device was to produce a steady stream of hot air that would cause the popping action. Because no oil was necessary, the popcorn was considered to be healthier. Salt and other spices could be added after the corn prepared with a hot air popper was poured into a serving bowl.

The advent of the microwave oven changed the way most people enjoy this treat. Today, many people purchase packages of microwave popcorn that can be popped within three to four minutes. Along with low fat versions, it is also possible to purchase bags flavored with a variety of spices and herbs, as well as with a caramel coating.

Microwave ovens spawned many variations of easy-to-cook popcorn.
Microwave ovens spawned many variations of easy-to-cook popcorn.

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Discussion Comments


Is it possible to make popcorn from any type of corn, or does it have to be a special kind? I live in an area that grows a lot of corn, and I have always wondered this. My friend claims you can, but I don't think so. We've never been motivated enough to swipe a couple ears from a field and try it.

The corn that's grown around me is used for animal silage. It is a lot harder than normal sweet corn. It also has smaller kernels, which makes me think there isn't much water in them.

@jcraig - I love kettle corn! I never tried it until four or five years ago when a friend introduced me to it. I have loved it ever since. For a while I could only find it at the fairs. Fortunately, the major companies caught onto it, and now you can find it in the bags.

I remember when I was younger, there used to also be a brand, I think it was Act II popcorn, that had little flavor packets with the popcorn. I can't find anything like that anymore. I guess it wouldn't be that hard to do yourself, though. I think they had some that were types of cheese, but my favorite was a spicy jalapeno flavor.


I know a lot of people that like the stuff in the popcorn tins, but I have never been a big fan. It always tastes kind of old and stale to me, even though the cheese or caramel can be good. There's nothing quite like fresh popcorn.

After reading this, I might start looking into a few healthier ways to cook popcorn, since it's something I do pretty regularly. To be honest, I'm not that big of a fan of the super buttered popcorn. I just think it is too greasy. What I really like is the kettle-cooked kinds that have a little sugar with them.


@julies - That is funny, because the same thing happens in my office. We always keep several bags of popcorn in the room. If we are working on a project or can't grab lunch for some reason, we will take a break and do to the kitchen to pop a couple bags. By the time we're done, we've always got a couple people nosing around trying to get a couple free bites.

I have never heard of the hot air poppers, though. Since we eat quite a bit of popcorn, that might be something we'd be willing to invest in to leave in the office. We always like things like that anyway. One guy found an old electric coffee percolator at a yard sale a while back, and that's what we use to make our coffee now.


I keep microwave popcorn bags in my desk at work. There are many days when I don't have much time for lunch and I will put one of these in the microwave and eat the popcorn at my desk.

It always smells so good that some of the other people in the office will end up doing the same thing. To me, popcorn always smells good when it it is popping no matter if I am hungry or not.


I also love popcorn, but really don't care for popcorn made with a hot air popper. I find it to be not nearly as tasty as popcorn popped in oil.

We use an electric popcorn popper with coconut oil. This is a healthy oil and we keep different popcorn seasonings on hand. One thing we noticed when using the coconut oil was the popper was so much easier to clean than using something like vegetable oil.

The younger kids really love to watch the popcorn pop and fill the whole bowl with big kernels.


I have made popcorn just about every way described in this article. This is one of my favorite all time snacks, and I have never found a way of making popcorn that I didn't like.

I have a hot air popper that sits on my kitchen counter. I keep this sitting out and make myself some popcorn about 5 times a week.

I know that using a microwave would be easier, but I like being able to enjoy the popcorn without all the extra calories. It only takes a couple minute for the corn to pop, and I add my favorite seasonings and enjoy a big bowl of popcorn without any guilt.

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