Dear readers, I am sharing with you the process of rice milling today. The next time you rip open a pack of rice, you know that a lot of work has gone into bringing it to you - from paddy grown in a field by a farmer, to the whitening of brown rice in a rice mill!
Pre-cleaning - Paddy arrives at the rice mill with a lot of impurities - like dirt, stones, straw and weed seeds. It is sent for pre-cleaning, i.e. passed through screens in order to get rid of these impurities and unfilled grains. A combination of screens is used for this purpose. First, course screens remove objects that are larger than the rice grains - such as stones and straw. Then, fine screens separate rice grains from the objects that are smaller than them - like dirt, weed seeds and broken grains.
Destoning - Pre-cleaning does not remove all the stones. The paddy is then passed through a gravity table, for this purpose.
Husking/ De-hulling - The husk is the tough outer layer coating of rice. The pre-cleaned paddy is next sent to the husking machine. There are more than one type of husking machines - rubber roller husker, steel huller and under runner disk sheller, all do the same job. Huskers use friction to remove the husk. The paddy is passed through two surfaces, moving at different speeds. As it presses tightly against these surfaces, the unwanted husk comes off. The result is brown rice!
Husk Aspiration - A portion of paddy retains its husk even after husking. (The amount of unhusked paddy depends upon on the efficiency of the huller.) Hence, the result of husking is a mix of husks, brown rice, unhusked paddy kernels and even broken grains. The husk is removed and discarded with a huller aspirator.
Paddy Separation - Next, the unhusked paddy is separated from the brown rice, using a paddy separator. These machines use the difference in the gravity of brown rice and unhusked rice to separate the two. The paddy kernels are sent back for husking.
Whitening - It is now time to turn brown rice into white. The brown-coloured bran, along with the germ, is removed. Like husk, the bran is also a hard coating, though its consumption is beneficial for human health. The germ is the reproductive part of the rice grain. There are many machines designed for rice whitening.
Polishing - Polishing is done to improve the look of rice grains. Both whitening and polishing processes cause breakage of rice. This is because these processes apply pressure to the rice grains. A mist of water is often used to give the grains a clean, smooth appearance.
Length Grading - It is now time to remove the broken pieces of rice, which greatly vary in size. Rice Pack separates these broken bits from "head rice". (Unbroken kernels)
Blending/ Mixing - Top-quality rice contains minimal broken kernels. The better the quality, the lesser is the amount of broken pieces. Broken pieces are also sold separately, and are consumed in many parts of the world. Head rice is mixed with a fixed amount of broken kernels in this step.