Rice storage facilities take many forms depending on
the quantity of grain to be stored,
the purpose of storage, and
the location of the store.
In general, it is recommended that rice for food purposes be stored in paddy form (=threshed, unhulled rice) rather than milled rice as the husk provides some protection against insects and helps prevent quality deterioration. However, when rice can be stored as brown rice, 20% less storage capacity will be needed. Brown rice is rice grain with its hulls removed but not polished.
Paddy rice (left), brown rice (center) and milled rice (right)
The requirements for a good storage system include:
Prevention of moisture re-entering the grain after drying
Protection from insects, rodents and birds
Ease of loading and unloading.
Efficient use of space
Ease of maintenance and management.
Rice grain is hygroscopic and in open storage systems the grain moisture content will eventually equilibrate with the surrounding air. High relative humidity and high temperatures contribute to high equilibrium or final moisture content.
In many tropical countries, the equilibrium moisture content is above safe storage moisture levels!
(For more info on Equilibrium moisture content and Equilibrium Relative Humidity, click here)