The Science Behind: Popcorn!
You shake the pot. You move the kernels. You prepare the salt. Then there’s a pop! You wait for more. And wait. And wait. And wait just a bit longer…Still nothing.
Popcorn is an incredible food — and by far one of my favorites. It’s good for you (without a pound of butter and salt), mildly salty, chewy, and absolutely delicious. And, of course, store-bought popcorn simply can’t compare to the freshly-popped, hand-seasoned popcorn made in your own kitchen. But this ideal situation leaves you with one problem: what if it just doesn’t pop? Unfortunately, you’re probably far from a popcorn popping pro. So, to resolve this horrific dilemma, let’s learn about the science behind popcorn.
What’s in it?
In reality, popcorn has two layers: a hull and an endosperm.
The hull is the outermost — and most important — layer. This protective layer is made of several sheets of cellulose — an organic compound that is often a part of cell walls in plants — and prevents any moisture from escaping the popcorn kernel before and during popping, which is key to the perfect pop.
The endosperm is the inner — and most delicious — layer. Before popping, the endosperm is tooth-breakingly hard. About 14 percent of the endosperm is made of moisture and the rest of it is starch.
How does it pop?
Once a popcorn kernel is heated, the science starts to happen. The heat causes the moisture in the endosperm to turn into steam. Ideally, the hard, impermeable hull will not allow this steam to escape. This situation will cause an increase in pressure.
As pressure increases, so does temperature. The pressure and temperature in the popcorn kernel continue to grow, and eventually, the temperature is high enough to change it from an impenetrable solid to a malleable substance that the high pressure can overcome to escape. The pressure now overpowers the weakened hull.
But how does popcorn get its poof? Well, this characteristic happens for similar reasons. The high temperature in the almost-popped popcorn makes the once-rock-solid starch into a jelly-like substance. When the hull finally breaks, all of the steam that was building up in the kernel escapes. As the steam escapes, it brings the jelly-like starch with it, expanding the endosperm. However, once the endosperm is on the outside of the kernel, it is surrounded by colder air, causing it to return to a solid state.
Why might my popcorn not pop and how can I troubleshoot?
The most common reason for a poor pop is a faulty hull. Since the hull is the main part of the kernel that keeps moisture inside and holds it together, if the hull has a leak, the kernel will lose moisture over time and steam and pressure will escape before popping the kernel.
Another possible cause for failure is poor heating. If corn is heated slowly, at a low temperature, or in wet heat — submerged in water, oil, or another liquid — the kernel may not gain enough pressure for it to pop. Instead, the kernel would be heated unevenly, possibly causing the hull to break in only one spot before the entire kernel is hot enough and has a high enough pressure to join this spot and pop.
Unfortunately, there are no ways to repair popcorn kernels that didn’t or unevenly popped. However, both of these situations are avoidable.
When the cellulose sheets making up the hull are heated, they crystallize and bond tightly together, keeping in all moisture and pressure. So, the more crystallization that the hull undergoes, the better pop it will have. Unfortunately, this information is only valuable for popcorn breeders — popcorn brands don’t generally advertise the exact breed of popcorn that they use.
The second problem has a simple solution: pop your popcorn on a high heat, heated by a small amount of oil or air — there aren’t many deep-fried or slow cooker popcorn recipes out there for a reason.
How should I enjoy it?
Any time, anywhere, any place. Popcorn is an incredible food that fits in any situation. Now, with this knowledge, it is time for you to science your way through your own bowl of perfect popcorn!
Works Cited
Moncel, Bethany. “The Science Behind Why Popcorn Pops.” The Spruce Eats, Dotdash, 19 Nov. 2018, www.thespruceeats.com/why-does-popcorn-pop-1328691. Accessed 26 Jan. 2019.
Skloot, Rebecca. “Why Popcorn Doesn’t Pop.” The New York Times Magazine, New York Times, 11 Dec. 2005, www.nytimes.com/2005/12/11/magazine/why-popcorn-doesnt-pop.html. Accessed 26 Jan. 2019.
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