Corn was winnowed,

By being thrown up by a shovel against the wind. As a rule this was done in the evening or during the night, when the west wind from the sea was blowing, which was a moderate breeze and fitted for the purpose. The north wind was too strong, and the east wind came in gusts.

By the use of a fan or van, by which the chaff was blown away ( Ruth 3:2 ; Isaiah 30:24 ; Jeremiah 4:11 Jeremiah 4:12 ; Matthew 3:12 ).

These dictionary topics are from
M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition,
published by Thomas Nelson, 1897. Public Domain, copy freely.