What Makes Popcorn Pop?

What Makes Popcorn Pop - Properties of Corn for Popping
by Debra Karplus

Corn on the cob, grits, corn flakes, nachos, tortillas, corn bread, and popcorn are a few foods produced from corn that many people enjoy eating. Corn is cultivated in most of the fifty states; its tall stalks can often be easily recognized. Many people don’t realize that the corn used for making popcorn is a different crop than corn on the cob and other edible corn products.

There are several varieties of corn grown both for animal feed and for people to eat. Flint corn is one kind of sweet corn. A type of flint corn is popcorn. Horticulturists refer to it by its Latin name, zea praecox. Grown best in temperate climates, in rich, fertile soil that drains well, popcorn is one of the oldest corn crops, cultivated as early as 3600 B.C. It’s harvested like other varieties of corn, in the autumn when the corn silk, the stringy portion directly covering the cob, turns brown. The cob is picked; the kernels are dried while still on the cob for four to six weeks, and then removed from the cob and ready to use in the kitchen. Though most corn kernels can pop, corn grown specifically for popcorn is optimal for flavor, texture, and popping speed.

The unique qualities of popcorn seed provide it with its ability to pop. It has a hard outer shell and inside contains moisture from the horny endosperm, tough, stretchy material that can resist the pressure of steam. Popping corn has more of this starchy inside than other corn varieties. When heated, steam is created inside the kernel. Pressure from this steam causes the popcorn to essentially turn itself inside out and “explode’ or pop.

Popcorn comes in different shapes; Pearl is the smooth variety, rice popcorn is elongated. Additionally, popcorn grows in different colors. It’s commonly grown as white or yellow popcorn. But, don’t be surprised to discover red, pink, blue or multicolored varieties. The appearance of these crops growing in the field is similar, as is the taste of the popped kernels.