Processing of rice

Several operations are involved in turning paddy rice to a well milled silky-white rice and making it easier to cook

Small scale processing 
Threshing
This is done to separate paddy from the straw and can done by mechanical devices or by trampling with feet or by pounding the rice ears in the mortal by pestle. Threshing floor should be very clean to prevent contamination by stones, and other particles. The problems associated with this method are: breaking of grains; mixture with stones and sands; low capacity of threshing, it's labour intensive and consumes energy.

Winnowing
This is done after threshing to separate the chaff and other contaminants from the paddy. The mixture is poured into a flat tray where it will be shaken continuously to toss up and blow away chaff and other particles while the remaining contaminants will be removed by hand. Ineffective separation and loss off paddy are the disadvantages of this method.

Drying 
The paddy must be dried to a safe moisture content level. Sun-dry the paddy for 2-3 days on a clean and stone-free platform to avoid contamination by foreign materials.

Parboiling
This is done by soaking rice paddy in water at ambient temperature, followed by boiling or steaming the steeped rice at 100% to gelatinize the starch. The paddy expands, thus making the hull's lemna and palea  to separate. The parboiled rice is then cooled and sun-dried before storage or milling. Parboiling gelatinizes the rice starch, make the rice grains harder and increase the milling yields. It also improves storage, milling, cooking and eating qualities. After parboiling the rice is dried to a safe moisture content before being bagged for storage and transport.

Drying after parboiling
The rice must be dried to 13 - 14% moisture content, and this must be done as soon as possible to avoid growth of mould.

Milling
This is the process of cleaning, dehusking, polishing and grading of rice grains or reduction of the grain size to flour.

Cleaning
Remove all contaminants or foreign substances before the entire milling process

Dehusking
The process of removing husks from the paddy, and can be done with local tools or mechanical devices.

Removal of bran and polishing
This is done to change the appearance of rice grains to white in order to improve the the taste and texture. It can be done locally by mixing the bran rice with the straws of dewatered sugar cane or guinea corn husks and then pound in a mortal until the grains turn white. The sugar cane chaff and guinea corn husks serve as abrasive materials. Rice processing and milling machines are used for large-scale processing, packaging and branding of rice grains.