Grab some popcorn and get ready to learn. Inspired by this answer on Quora.
1. First things first, you can’t make just any type of corn pop.
You have to use – yep – popping corn, a type of corn that, crucially, has a hard outer shell. Just in case you’ve never made popcorn yourself and haven’t seen it before, this is what it looks like before it pops:
2. When you heat the popcorn up, the tiny bit of water inside the kernel changes into steam and expands.
When there’s no more room to expand inside the kernel and the pressure gets too high, it explodes, as demonstrated in this GIF from a video by the Slow Mo Guys.
3. According to The Popcorn Board:
Around 212 degrees [Fahrenheit] the water turns into steam and changes the starch inside each kernel into a superhot gelatinous goop. The kernel continues to heat to about 347 degrees. The pressure inside the grain will reach 135 pounds per square inch before finally bursting the hull open.
As it explodes, steam inside the kernel is released. The soft starch inside the popcorn becomes inflated and spills out, cooling immediately and forming into the odd shape we know and love.
4. But the fun doesn’t end there. There are actually two types of popcorn: mushroom and butterfly.
According to Speciality Corns by Arnel R. Hallauer, butterfly popcorn (right) “is associated with tenderness and freedom from hulls” whereas mushroom popcorn (left) is more suited to coating with flavourings because it can withstand handling.
5. The two types form in slightly different ways.
With mushroom popcorn, the kernel expands evenly. But with butterfly popcorn, the starch inside comes out of wherever the kernel’s skin breaks, basically turning it inside out. You can see butterfly popcorn forming in these GIFs: