The three most widely available millets in the market place today - Sorghum, Pearl millet and Finger millet - are naked grains, i.e. do not have a husk layer. Processing these for human consumption is essentially a matter of cleaning and grading the grains. They are then ground up to either their flour form or into grits making them ready for cooking. This ease of processing is one of the reasons for these grains to persist in the local communities' diets.
There are six other commonly cultivated millets - Foxtail, Little, Kodo, Proso, Barnyard, and Brown Top - that have a hard cellulosic husk layer that humans cannot digest. Together they are sometimes referred to as small millets. The removal of the husk layer thus becomes the primary task of processing these grains. Once removed, we get the respective millets' rice, i.e. foxtail millet rice, little millet rice, kodo millet rice, proso millet rice, barnyard millet rice and brown top millet rice. These millet rices are then used in preparations in the same form and method that paddy rice is used in different cuisines.
To remove the husk from the grain, one can use two forces - impact or shear. A stone grinding mill- manual or motor powered-employs shear force while manual pounding or centrifugal hulling machines use impact force.
Large scale processing of small millets compromises the nutritional value of the millet rice output by removing the bran layer completely. But the pest infestation problem continues to be severe and most processors resort to chemical methods of cleaning their products pest free.
At the other end of the supply chain, the lack of small scale processing has adversely affected the availability of the processed millets for use by the farming communities themselves - a rural household cannot afford to buy millet rice from the market. Small scale processing machines and process flows have been developed. But the inherent variations in the harvested grains' characteristics is significant. This problem magnifies when the small millets are aggregated for processing. So in that sense, there is an inherent advantage in small scale processing. But a big stumbling block in achieving good quality millet output, i.e. clean small millet rices with minimum bran loss, is the lack of skilled operators who understand the grains and are trained in using the right tools and machines.