Winnowing follows threshing and uses wind, fans, or mechanical airflow to carry away husks while the heavier grain falls back. The process transforms a dusty mixture into a valuable, purified harvest. In poetry, it is a natural metaphor for discrimination, judgement, cleansing, and the separation of truth from worthlessness. Biblical language gives winnowing moral and spiritual force, but poets may also use its windblown chaff and rhythmic tossing for vivid sensory description of communal agricultural work.

Winnowing separates heavier grain from lighter chaff by tossing the mixture into moving air or passing it through a fan. It normally follows threshing. Because wind carries away what has little weight, poetry frequently uses winnowing as a metaphor for judgement, purification, testing, and the discovery of genuine value. Related terms include grain, chaff, threshing, winnowing basket, fan, harvest, threshing floor, separation, and breeze.