What’s with the popcorn kernels that don’t pop?


I have no idea what the right flair for this is, sorry.

In: Physics

Popcorn pops because of steam pressure. The inside of the kernel contains starch and water, which are contained in a hard shell. When you heat it, the starch liquifies and the water turns to steam. When the steam pressure gets high enough, the shell explodes, the starch instantly solidifies, and the corn is popped.

If the shell is broken, steam won’t build up. Bad kernel

If it is too dried out, not enough pressure will build up. Bad kernal

In my experience usually it’s because they don’t get hot fast enough and so the shell just cracks letting all the steam out and they never explode. The best way to get around this is to heat the pan with the oil in it to about 350° and then put all the kernels in. This way you have very few old maids left at the bottom.

All the kernels have different amounts of water inside. Water heating causes popping. Some kernels don’t get as much heat as others, some have less water. Too cold, or too dry, no popping.

Popcorn kernels that don’t pop usually pop on the second go, due to the heat they already had and are now having

Source: popcorn machine owner

Mythbusters did an episode on this. Everyone tried to get the most popped kernels out of their batch. I don’t remember what happened tho.

I now use a thin aluminum popper, the Whitley-Pop, and I almost never have “old soldiers” anymore.

Popcorn kernels pop because they absorb heat energy until they reach a critical level and pop. When there are lots of unpopped kernels, most of the heat energy gets absorbed by the kernels. But when most of the kernels have popped, less energy gets taken in by kernels. The heat levels haven’t gone down though, so the excess heat energy goes into the already popped kernels more and more. At a certain point the popped kernels start to burn. Since you don’t want burnt popcorn, you stop the cooking before that happens.

To piggyback off of this. I know you can overcook the whole bag but even when stopping the microwave at the perfect time, what keeps the early poppers from burning?

The only time that I really get a lot of old maids is when I don’t use enough oil in the pot. I always use olive oil with a bit of ghee to add a buttery flavor (about 2tb oil, 1.5ts ghee for about half a cup of kernels).

They’re a lot like your mom, champ. You see, she was a late bloomer or maybe even not a bloomer too, all the other girls had popped and were definitely tasty snacks. They’d been chewed up and consumed by all of the other fellas here in town. Not your mom though… No it took a lot of time for her to blossom, but eventually all those other girls were used up and had families of their own. But me and your mom kiddo, well we took our time and eventually we found each other in the trash heap of town, and there surrounded by the discarded crust of our little community we made you! Our very special little kernel. I still have to put a bag over her head and wait a few minutes for her to get steamy, but kiddo, she gets HOT. Find one like her and you’ll never go hungry.

Primarily, if the hull of the kernel is damaged in any way, the kernel may not build up the pressure to pop.

Also, if the heat of the kettle is not enough to pop the corn (such as other kernels are wicking away heat when they pop) the heat is still enough to cook the corn, ensuring that it never will, as it is basically scorched.

In addition, if it is an oil-type kettle, there is a need to have enough oil, or again, heat transfer can be enough to fry the kernel, but there isn’t enough oil to provide all the heat you’d need to pop it. Too little, and you can scorch some of the kernels, and too much oil, you can deep fry the kernels which will cause some of them to split in a ‘bad way, releasing the pressure needed for the popping to occur before there is enough heat to cause the moisture in the kernel to expand.

It bears pointing out that hot oil poppers are more efficient at getting the most popcorn out of the kernels you put in, but hot air poppers are, though less gentle (which results in cracked hulls), are healthier.

I work in the cinema exhibitor industry, and yes, there are courses that give you all this information, which is why I have all of this information from working in this industry for 29 years.

As a side note: popcorn kernels are usually either one of a specific number of strains of corn (most common), or they are prepared and dried in a certain way. You CAN pop any corn kernel, but the amount of popcorn you get is much lower than using the kernels that are bred as popcorn kernels.

Too boring? Kernels that don’t pop are a result of being cracked, burned, or cooked at a temperature below what is needed to cause the water to expand, and if you just use ‘regular corn’, the moisture content isn’t right in most of the kernels to get a lot of popped popcorn out of it.