Have you heard of the phrase ‘separating the wheat from the chaff’? It’s likely that you didn’t give too much thought to the saying, but the origins of this adage are not only ancient but essential to harvesting cereal crops. Basically, it refers to separating seeds from chaff. What is chaff and why is seed and chaff separation important?

About Separating Seeds from Chaff
Before we get to the definition of chaff, a little background on the make-up of cereal crops such as wheat, rice, barley, oats, and others is helpful. Cereal crops are made up of the seed or the grain kernel that we eat and an inedible hull or husk surrounding it. Seed and chaff separation is imperative because in order to process and eat the grain kernel, the inedible hull needs to be removed. This is a two-step process involving threshing and winnowing.

Threshing means loosening the hull from the grain kernel while winnowing means to get rid of the hull. Winnowing can’t very well occur without threshing first, although some grains have a thin papery hull that is easily removed so little threshing is required. If this is the case, traditionally, farmers would just toss the grain into the air and allow the air current to blow the thin hulls, or chaff, away in the wind or to fall through the slats of the basket.

This wind assisted process of removing the chaff from the grain is called winnowing and the grains with little to no hull are called ‘naked’ grains. So, to answer the question of what is chaff, it is the inedible hull surrounding the grain.

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