Each kernel has a percentage of moisture inside.
Without the moisture, the kernel will be unable to pop. What is also needed for popcorn to "pop", is heat.
Either a microwave, popcorn popper, or simply in a pot on the stove. When the popcorn kernels are heated, the moisture inside the kernel expands putting pressure against the starch inside the kernel. When the water pressure inside the hard shell get high enough, the kernel will then explode. The soft starch inside the kernel will inflate and burst, turning the kernel inside out, releasing the steam inside and exposing the airy foam we see as popcorn!
- Kernels that do not pop are known as "old maids". They are basically too dry, and have no pop left in them!
- Buttered popcorn sells twice as well as plain popcorn.
- The average popping temperature for popcorn is around 175°C.