Winnowing

We are using a lot of separation techniques to separate mixtures in our daily life. The separation technique is primarily based on the nature of components in that mixture. Filtration, hand picking, decanting, sieving etc., are the basic separation techniques that we are adopting in our daily life. Have you ever thought of how the grains that we are directly using from the market are processed? Is there any separation technique to separate the grain from the chaff? The answer is yes. And that separation technique is known as winnowing, which means separation with the help of wind. In this topic, we are discussing what is winnowing, its uses, advantages and disadvantages.

What is Winnowing?

Winnowing is a separation technique in which lighter particles from heavier components are separated out either by blowing air or by the wind. This is basically used to separate grains from the chaff in the paddy field. In traditional winnowing, the dried grains were allowed to fall from a definite height using a shovel and sieve. During this, lighter particles flew in the air, and the heavier particles fell down. It is an important step in agriculture. Through this process of separation, we are getting clean grains. In grains, chaff is present; this chaff is lighter particles, so during winnowing, it will fly into the air, and heavier grains fall down.

Principle of Winnowing

The winnowing principle is based on the difference in mass between components. If a mixture contains two components, one is lighter in weight compared to the other one, then it can be separated by winnowing. The mixture is allowed to fall down from a height while the wind is blowing through it lighter components will blow off by the wind, and the heavier component will fall down.

Significance of Winnowing in Agriculture

As said before, winnowing is an important process in agriculture. It is done after the process of threshing in the cleaning process of grains. The purpose of winnowing is the removal of chaff. Chaff is the protective casing of seed. It is dry and scaly. The human intestine cannot digest this chaff. Hence it should be removed even after threshing chaff may not be removed. So winnowing is done to remove these lighter particles.

Winnowing Techniques

Winnowing is used to remove lighter chaff from grains in the paddy field. Traditional winnowing depends on the natural wind. In this process, dried grains are allowed to fall from a height using a shovel and sieve. It has a lot of limitations, like it can not carry out in the rainy season, and farmers have to wait for the wind and should know the direction of the wind also.

To overcome this, in 1737, Andrew Rodger invented the machine called fanner. It can produce wind artificially, and it is considered the first winnowing machine. Nowadays, so many winnowing machines are available in the market. It has pedals so that the speed of wind can be adjusted. These machines made the winnowing process easy. Now we can do winnowing in a closed room, and tons of grains can be cleaned within a very short span of time.

Winnowing fan is another technique of winnowing. A traditional winnowing fan is a specially shaped basket in which grains are shaken, and the lighter particles are blown away with the wind. Nowadays, these winnowing fans are machines which can produce artificial wind. It can be made from bamboo, cane, and paper also.

The winnowing fork is another technique. In which a tool similar to a pitchfork is used to remove the chaff from grains with the help of wind. By winnowing, fork-harvested grains are lifted into the wind. Then chaff particles blow away with the wind, and grains fall to the threshing floor.

Advantages of Winnowing

• Winnowing is a crucial process in the cleaning of grain

• Winnowing helps to remove indigestive chaff from grains, and this chaff can give to livestock

• Winnowing machines are eas

• To handle, pollution free, and has less maintenance.

• Grains like wheat, rice, corn etc., can be cleaned by this process.

Disadvantages of Winnowing

• Through this process, we can separate light impurities like chaff

• We can not separate impurities heavier than a grain

• Impurities like stones can not be removed

• The scope of separation of impurities is limited in winnowing.

Applications of Winnowing

• The husk of wheat can be removed

• Straw from corn can be removed.

• Impurities in the grains can be removed.

Interesting Facts About Winnowing

• The first winnowing machine was invented in 1737, called fanner by Andrew Rodger.

• A rotary winnowing fan can produce an air stream is used by ancient china to improve winnowing.

• In 1700 these rotary winnowing fans were exported to Europe by Dutch.

Key Features

• Winnowing separates lighter impurities from heavier components with the help of wind.

• This technique is used in agriculture to clean grains by removing chaff.

• Traditional winnowing was carried out by using a shovel and sieve.

• Winnowing fan and winnowing fork are other winnowing tools.

Difference Between Winnowing and Threshing

Conclusion

The study notes on Winnowing provide a complete overview of the process of winnowing, including an overview of its origin, description, and the advances made in the process with the progress of industrialization.