Seed to Seed Quality
       
  What is an ideal moisture content for dried paddy rice and how is it reached?  
  Identify the correct moisture content for paddy rice after drying and describe two drying methods: sun and mechanical.  
     
When is enough enough?
 

Paddy should be dried to 13-14% moisture as soon as possible after threshing. Quality is maintained by drying and tempering the grain a number of times, or in stages during the drying process.

Wet spots in the grain due to uneven drying or weed seeds can lead to off odors and discoloration of the grain.

  
Sun drying
   When sun-drying, two tasks are important: 1) spreading and turning and 2) monitoring temperature. Click the appropriate button in the below image to learn more about these tasks.  
   
Mechanical drying
 

Grain is also dried in mechanical batch dryers. The most common smaller dryers have a capacity of 1-3 tons per day with drying times of 6-12 hours. The following table describes appropriate settings for common bulk driers:

Setting Value
Temperature For drying of paddy in tropical areas, an air temperature of 40-45°C is normally used with a heater capable of raising the air temperature 10-15°C
Air velocity 0.15 - 0.25m/s
Power requirements 1.5 - 2.5kW/ton of paddy
NOTE: The efficiency of these dryers is also improved by stirring the grain or by unloading and reloading the dryer.

 
Next lesson
   The paddy rice is now dried to the appropriate moisture content of 13-14%. Now it's time to for proper storage. In the next lesson, you will learn about traditional and modern forms of paddy rice storage.