The science of popping popcorn | Hey Ray
PITTSBURGH (KDKA) - A tiny kernel of popcorn has a lot of science packed into it. It is a staple snack for movies, and tons of kernels have been popped and enjoyed, but how does one, hard kernel become a fluffy piece of popcorn?
What happens to make this transition?
According to Popcorn.org, Popcorn differs from other types of corn because its hull, or outer shell needs to have just the right thickness to allow it to burst open when that kernel is heated up. There also needs to be a little moisture inside each kernel. A precise amount of moisture, actually. The inside needs to be 13.5-14% moisture.
If you ever popped popcorn, you know you need heat. That moisture inside the kernel warms up to the boiling point of 212° and turns to steam. This increases the pressure inside the kernel. Once that pressure builds enough, the outside of the kernel breaks, allowing the inside, fluffy part to come out.
The National Agriculture Library says a kernel has a hard starch on the outside and a soft starch on the inside. Once you heat the kernel to a pressure level strong enough, the hard starch exterior breaks, inflating the soft starch interior, and allowing it to congeal and pop out and turn into that is the part you eat.
Sometimes, you're left with kernels that don't pop. There needs to be enough moisture, and the outside husk or shell needs to be able to trap that moisture long enough for the pressure to build. If you can't turn that moisture to steam, and the pressure can't build you will not get a pop!