A popcorn kernels is a type of maize, or corn, kernel that comes from a wild grass called zea mays everta. Popcorn is one of six types of corn, but The Popcorn Board notes that zea mays everta is the only variety to produce kernels that pop.
Farmers harvest popcorn using combines that remove the ears from the stalks. The ears are stored for up to a year until the kernels' moisture levels reach 14 percent, according to The Popcorn Board. The kernels can be stripped from the ears before or after they have dried. The dry kernels are sorted, cleaned and polished before they are packaged for sale.
Popcorn pops because of the water contained in each kernel. Jones Popcorn notes that when heated, the water turns to steam, and the pressure the steam exerts causes the shell of the kernel to burst.