Extension Educator, Horticulture
Do you ever wonder who was the first person to figure out that popcorn popped? I'm sure it was a woman. With popcorn she could feed the family without spending so much time in front of the grain grinding stone. Just throw some corn kernels in a hot bowl and it's time for supper. Popcorn – the first step in the creation of "leisure time".
According to the United States Department of Agriculture the oldest ears of popcorn date to about 5,600 years ago and were found in the Bat Cave in New Mexico. The size of the ears varied from smaller than a penny to about 2 inches long. Surprisingly they still popped.
Even though popcorn has a long history it wasn't until 1880 that it showed up in farm information and seed catalogs. Popcorn was one of the few affordable treats during the Depression and World War II.
The United States is the leader in the production of the world's popcorn. Most popcorn is grown in Nebraska and Indiana, but also in Illinois, Ohio and Missouri. The average American eats about 68 quarts of popcorn a year.
So why does popcorn pop? Native American stories describe spirits who live inside each kernel of popcorn. The spirits are quiet and content living in the kernels but grow angry when there homes are heated. The hotter their homes, the angrier they become. The kernels shake and shimmy with their anger until the heat is too much. The spirits burst out of their homes and into the air as disgruntled puffs of steam.
Ok, if you don't buy the spirit story then how about this. Each hard kernel of popcorn has a small amount of water stored inside a sphere of soft starch. As the kernels are heated, the water expands as it turns to vapor. The pressure eventually breaks the hard outer surface as the starch inflates and basically turns the kernel inside out. For this to work well the kernel has to be relatively small, and the hard outer shell of the kernel must be quite strong to resist the increasing pressure. This explains why popcorn has kernels that are smaller than most field corn.
There are basically two types of popcorn: round pearl kernels usually produced on large ears and sharp-pointed rice kernels usually produced on small ears. Pearl type (what you usually find commercially) produce large whole hulls when popped. Rice type produce smaller popped corn but it is tender and has little or no hull (that thing that gets caught in your teeth). Rice types are especially prized by home gardeners or can be purchased in specialty shops.
Popcorn can be successfully grown in large home gardens. Despite what most kids think, it doesn't come in a bag labeled "this side up".
Kernel colors vary from the usual white and yellow to red, brown, black, blue and even multicolored. Some popcorn varieties for home gardens include rice types Japanese Hulless – white; Purdue 307 – white; Purdue 608 – yellow; Strawberry – red, ornamental and tasty; Cutie Blues - solid dark blue; and Cutie Pops – calico.
The key to the pop is the water. Popcorn needs to have a moisture content of 13-14 %. If you have popcorn that just doesn't pop anymore, it has probably gotten too dry. To correct the problem place unpopped corn in glass quart jar. Put in 1 tablespoon of water. Seal tightly and shake jar well. One hour later shake again. Over the next 4-7 days shake jar vigorously 2 to 3 times a day. Store in airtight container or in freezer to maintain moisture.
Several companies make microwave popcorn poppers for preparing your home grown treats.
For more popcorn information: http://www.nal.usda.gov/speccoll/images1/popcorn.html