Drying

postharvest-drying-manual-2Drying reduces grain moisture content to a safe level for storage. It is the most critical operation after harvesting a rice crop. 

When rice is harvested, it will contain up to 25% moisture. High moisture level during storage can lead to grain discoloration, encourage development of molds, and increase the likelihood of attack from pests. It can also decrease the germination rate of the rice seed.

drying-systems-diagramClick to zoom

It is important to dry rice grain as soon as possible after harvesting— ideally within 24 hours. Delays in drying, incomplete drying or ineffective drying will reduce grain quality and result in losses.

Paddy drying methods include traditional and mechanical systems with varying technological complexity and capacities for either farm or commercial level.


Drying systems

Drying systems

Drying can be done using either traditional or mechanical drying systems.

Drying basics

Drying basics

Since drying practices can have a big impact on grain quality or seed quality, it is important to understand some fundamentals of grain drying.

Drying strategies

Drying strategies

When developing a drying strategy, it is important to consider other activities in rice post production system, and look into the economic criteria

The Solar Bubble Dryer

The Solar Bubble Dryer

Solar drying is the latest in drying technology. In this method, sun drying is simulated using a solar bubble dryer which protects the grains despite changes in weather patterns and thus, prevents postharvest losses.

In-store drying

In-store drying

In in-store drying, the drying process continous until it reaches the equilibrium moisture content; thus, over drying of the bottom layer is minimized.

Sun drying

Sun drying

Sun drying is a traditional drying method for reducing the moisture content of paddy by spreading the grains under the sun. 

Economic aspects of drying

Economic aspects of drying

A guide to site-specific assessment on the potential of mechanical drying

Measuring moisture content

Measuring moisture content

Different moisture contents are required per postproduction operation. These should be followed to ensure good quality of paddy.

Heated air drying

Heated air drying

Heated air drying allows for suitable drying air conditions to be set. In this method, drying can be carried out any time of the day or night.