Chaff - Grain Chaff

Grain Chaff

In grasses (including cereals such as rice, barley, oats and wheat), the ripe seed is surrounded by thin, dry, scaly bracts (called glumes, lemmas and paleas), forming a dry husk (or hull) around the grain. Once it is removed it is often referred to as chaff.

In wild cereals and in the primitive domesticated einkorn, emmer and spelt wheats, the husks enclose each seed tightly. Before the grain can be used, the husks must be removed.

The process of loosening the chaff from the grain is called threshing – traditionally done by milling or pounding. Separating the loose chaff from the grain is called winnowing – traditionally done by tossing grain up into lightly blowing wind, dividing it from the lighter chaff, which is blown aside. This process typically utilizes a broad, plate-shaped basket, or similar receptacle for holding and collecting the winnowed grain as it falls back down.

Domesticated grains such as durum wheat and common wheat have been bred to have chaff which is easily removed. These varieties are known as free-threshing or naked.

Chaff should not be confused with bran, which is finer scaly material forming part of the grain itself.