Drying

Drying is the process of simultaneous heat and moisture transfer. It is the removal of excess moisture from the grains. Once dried, the rice grain, now called rough rice, is ready for processing. Proper drying results in increased storage life of the grains, prevention of deterioration in quality, reduction of biological respiration that leads to quality loss of grains, and optimum milling recovery.

In the country three methods are used for drying the paddy grains, namely :

• Sun drying
• Mechanical drying
• Chemical drying

Sun Drying
Sun drying is a traditional method of drying the paddy grains. In fact, the major quantity of produce is being dried in the country by this method. Sundrying is the most economical method of drying grains. Grains are spread on drying surfaces such as concrete pavement, mats, plastic sheets and even on fields to dry naturally.

Mechanical Drying
Mechanical drying process means drying the grains by ventilating natural or heated air through the grain mass to get it evaporated the moisture from it. Mechanical dryers are more reliable since drying could be done anytime of the year.

Chemical Drying
Chemical drying method involves the spraying of common salt solution with specific gravity of 1.1 to 1.2 on the ears of the mature paddy crop. This treatment reduces the moisture content from 29% to 14.5% after four days.