The oldest ears of popcorn ever found were discovered in the Bat Cave of west central New Mexico in 1948. Ranging from smaller than a penny to about 2 inches, the oldest Bat Cave ears are about 4,000 years old.
People have been fascinated by popcorn for centuries. Some Native Americans believed that a spirit lived inside each kernel of popcorn. When heated, the spirit grew angry and would eventually burst out of its home and into the air as a disgruntled puff of steam.
A less charming but more scientific explanation exists for why popcorn pops. Each kernel of popcorn contains a small drop of water stored inside a circle of soft starch. Popcorn needs between 13.5 to 14% moisture to pop. The soft starch is POPCORN surrounded by the kernel’s hard outer surface. As the kernel heats up, the water begins to expand. At around 100 degrees celsius the water turns into steam and changes the starch inside each kernel into a super hot gelatinous goop. The kernel continues to heat to about 175 degrees. The pressure inside the grain will reach 135 PSI before finally bursting the hull open. As it explodes, steam inside the kernel is released. The soft starch inside the popcorn becomes initated and spills out, cooling immediately and forming into the odd shape we know and love. A kernel will swell 40-50 times its original size.
Good popcorn should provide at least 98 percent popped kernels with well under two percent “spinsters” or unpopped kernels. Proper care at the processing level helps to assure this. Processors guard against contamination and other types of kernel damage which could lower popcorn quality.