Grain / Chaff

The Bible often uses things that were common to the lives of the people at the time they were written. Some of those things are not as common to us now. One of these is grain and chaff. Matthew 3:12, "For the winnowing fan is in his hand and he purges his threshing floor, and he gathers the wheat into his barns, and the chaff he will burn in fire that is not extinguished."

Grain grows on a long stalk with the seeds at the top. The seeds are ground into flour for making breads. Each seed has a little covering around it made from a tough material. This casing has a hair-thin tail on it about an inch or two long. Together these tails make what is called the beard. The casing and tail are called chaff. The chaff and the stalk and are only good for cattle food.

The harvesting process involves cutting the stocks free, beating them (threshing) to release the seeds, and then winnowing which removes the seeds from the chaff

¹ http://www.flourinfo.co.nz/index.php?option=com_content&view=article&id=8:wheat-the-structure-a-physical-characteristics&catid=4:wheat&Itemid=58