Popcorn is a tasty treat that many people enjoy. The history of popcorn dates back to ancient times, where it was first discovered by the Native Americans. People have been popping corn for centuries now and still love eating it today. Popcorn is an easy snack to make at home or you can buy bags of microwavable popcorn from your local grocery store too.
As legend has it, spirits lived inside popcorn kernels. While they lived peacefully, they would get mad if heated too much by someone’s stovetop or oven. When angered, they would shake out into a frustrated steam before bursting open.
You might be wondering how exactly does popcorn pop? It’s simple, but there are some interesting science facts behind why this happens.
- The secret is in the kernel.
Corn kernels have two layers. The outer layer, the yellow transparent hull is what you need for popping corn and it’s also where moisture won’t penetrate until popped. This acts as a pressure vessel during popping so your snack will stay fresh longer thanks to its insulation qualities.
Inside the hull is a hard starch and a small amount of moisture known as the endosperm. It is described to be as hard as a rock before it is popped. This is what people bite into when they try to eat an unpopped kernel.
- Heat plays a crucial role in the popping process.
When the kernel is heated, it swells and becomes pliable. The trapped water turns into steam as pressure builds inside of this hard shell.
The pressure from this heated environment causes moisture trapped inside the starchy structure to turn into steam, which penetrates past its boiling point and starts pushing through the hull.
When the pressure within a kernel reaches its limit, it ruptures and releases all of that energy as steam. The gelatinised starch inside quickly expands into an airy substance before stiffening back into solid form once more due to its boiling point dropping again after only seconds at room temperature (350 degrees Fahrenheit).
Why some kernels don’t pop
Every batch of popcorn has a few kernels that never pop or simply crack open without popping. There are several possible causes, but the most common is if there’s an area with cracks in it where pressure cannot build up so steam slowly leaks out until they’re done steaming. These stubborn pieces stay intact while other ones will split before the starch gelatinises, causing them to be basically “open” instead of compact like normal popped corn would be.
Also, it might seem like the most important factor in popping corn is what type of starch is inside the kernel, but not all starches are created equally. Scientists describe the starch as either hard or soft; it needs to be sufficiently strong to hold on to its shape but also soft enough to expand when heated.
Lastly, heating the corn the wrong way can result in unpopped kernels. Corn requires dry air or an oil-based pan heater in order for popping, which is caused by rapid heating of kernels at high enough temperatures within two minutes after emergence from their stalk but before they have burst open fully – this ensures pressure build-up without bursting apart too soon so that you get a perfect popper with no burned bits left floating around.