is an agricultural
method developed by ancient cultures for separating grain
. It is also used to remove weevils
or other pests from stored grain. Threshing
, the separation of grain or seeds from the husks and straw, is the step in the chaff-removal process that comes before winnowing.
In its simplest form it involves throwing the mixture into the air so that the wind blows away the lighter chaff, while the heavier grains fall back down for recovery. Techniques included using a winnowing fan (a shaped basket shaken to raise the chaff) or using a tool (a winnowing fork or shovel) on a pile of harvested grain.
In Ancient China the method was improved by mechanisation with the development of the rotary winnowing fan, which used a cranked fan to produce the airstream. This was featured in Wang Zhen
's book the Nong Shu
of 1313 AD. This technique was not adopted in Europe until the 1700s, when winnowing machines used a 'sail fan'.
In Greek culture
The winnowing-fan (liknon
) featured in the rites accorded Dionysus
and in the Eleusinian Mysteries
: "it was a simple agricultural implement taken over and mysticised by the religion of Dionysus," Jane Ellen Harrison
remarked. Dionysus Liknites
("Dionysus of the winnowing fan") was wakened by the Dionysian women, in this instance called Thyiades
, in a cave on Parnassus
high above Delphi
; the winnowing-fan links the god connected with the mystery religions
to the agricultural cycle, but mortal Greek babies too were laid in a winnowing-fan.. In Callimachus
' Hymn to Zeus
lays the infant Zeus in a golden liknon
; her goat suckles him and he is given honey.
In the Odyssey, the dead oracle Teiresias tells Odysseus to walk away from Ithaca with an oar until a wayfarer tells him it is a winnowing fan, and there to build a shrine to Poseidon.
In the New Testament
In the Gospel according to Matthew
3.12, a sentence introduces the separation of wheat and chaff (good and bad) by "His winnowing fan is in his hand" (American Standard Bible
In the United States
The development of the winnowing barn
allowed rice plantations in South Carolina
to increase their yields dramatically.