Popcorn was first discovered thousands of years ago by the Native Americans, who believed that the popping noise was that of an angry god who escaped the kernel.
Each kernel of popcorn contains a certain amount of moisture and oil. Corn is able to pop because, unlike other grains, the outer hull of the kernel is both strong and impervious to moisture, and the starch inside consists almost entirely of a dense starchy filling. This allows pressure to build inside the kernel until an explosive pop results.
As the oil and the water are heated past the boiling point, they turn the moisture in the kernel into a superheated pressurized steam, contained within the moisture proof hull. Under these conditions, the starch inside the kernel gelatinizes, softening and becoming pliable. The pressure continues to increase until the breaking point of the hull is reached, a pressure of about 135 psi and a temperature of 356 °F. The hull ruptures rapidly, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into airy foam. As the foam rapidly cools, the starch and protein polymers set into the familiar crispy puff.
During the Great Depression, popcorn was comparatively cheap at 5 to 10 cents a bag and became popular. Thus, while other businesses failed, the popcorn business thrived and became a major source of income for some struggling farmers. During World War II, sugar rations diminished candy production causing Americans to eat three times more popcorn than they had before.
At least six localities, all in the United States, claim to be the Popcorn Capital of the World: Valparaiso, Indiana; Van Buren, Indiana; Marion, Ohio; Ridgway, Illinois; Schaller, Iowa; and North Loup, Nebraska. According to the USDA, most of the maize used for popcorn production is specifically planted for this purpose. Most is grown in Nebraska and Indiana, with increasing area in Texas. As the result of an elementary school project, popcorn became the official state snack food of Illinois.
Popcorn, threaded onto a string, is used as a wall or Christmas tree decoration in some parts of North America, as well as on the Balkan peninsula. The world’s largest popcorn ball was unveiled in October 2006 in Lake Forest, Illinois. It weighed 3,415 pounds, measured 8 feet in diameter, and had a circumference of 24.6 feet.