The Neatest Little Paper Ever Read ®

Issue 974



by Janet Spencer

Popcorn is one of the most popular snack foods. Come along with Tidbits as we chow down!


• Unpopped popcorn has a very long shelf life. In ancient tombs of Peru, archaeologists found kernels a thousand years old that still popped. An expedition found popped popcorn in a cave in Utah which was still remarkably fresh in spite of being around 2,500 years old. The oldest known popcorn kernels were found in a cave in New Mexico and are believed to be around 5,000 years old.

• One dig near Mexico City uncovered pollen of the popcorn plant. It was almost identical to modern popcorn pollen, yet it was 80,000 years old, indicating that humans have been enjoying popcorn for thousands of years. Cortez found the Aztecs eating it when he invaded in the early 1500s. Columbus took it back to Spain with him.

• The British and Europeans used to refer to any small kernel as “corn” such as in Jack London’s 1913 novel “John Barleycorn” named for the drinking song by the same name. Wheat, rye, oats, and barley were all called “corn” and the new corn from the New World was called “Indian corn” before being shortened to just “corn.” The words “corn” and “kernel” spring from the same root word “cyrnel” meaning “seed.”

• There are six types of corn: pod, sweet, flour, dent, flint, and popcorn. Only popcorn pops.

• Popcorn has a thicker hull than other kinds of corn, and the hull is not permeable. A popcorn kernel must have a moisture content of about 15% in order to pop. When cooking, the hull is so tight that the water within the kernel cannot escape until it boils into steam. The starchy interior melts into a gelatin. When the pressure gets high enough, the hull bursts and the heat cooks the soft interior. A kernel will pop when it reaches an internal pressure of 135 psi and a temperature of 356°F. If the water content falls below 15%, the popcorn won’t pop.

• Popping results are sensitive to the rate at which the kernels are heated. If heated too quickly, the steam reaches high pressures too soon and ruptures the hull before the starch in the center of the kernel can gelatinize, leading to partially popped kernels with hard centers. Heating too slowly leads to entirely unpopped kernels because the tip of the kernel is not entirely moisture-proof. When heated slowly, the steam can leak out of the tip fast enough to keep the pressure from rising high enough to break the hull and cause the pop.


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