FAQ

A rice milling system can be a simple one or two-step process, or a multi-stage process. • One step milling - husk and bran removal are done in one pass (White rice is produced directly from paddy). . • Two-step process - removing husk and removing bran are done separately. (Brown rice is produced as an in-between product) . • Multistage milling - The milling process in bigger commercial mills combines a number of operations that produce higher quality and higher yields of marketing or consumption white rice from paddy or rough rice. . Rice undergoes a number of different processing steps, such as: . 1. Pre-cleaning (Pre-cleaning the paddy prior to milling) 2. Dehusking or dehulling (Removing the husk or outer layer from the paddy) 3. Paddy separation (Separating the brown rice from the paddy that is not be husked) 4. Whitening or polishing (Polishing or whiting the brown rice to remove the bran layer) 5. Grading (Separating the broken grains from the whole kernels) 6. Mist polishing (Polishing or whiting the brown rice to remove the bran layer) 7. Weighing of rice (Bagging the milled rice)

The cost of rice mill basically depends upon the size and how much rice you want to produce. Nowadays rice mill is really profitable business, as the demand for rice is increased. If you want to set up the modern rice mill, the cost is not that high. But if you don’t have much capital, then don’t start with the automatic processing; therefore you need to dry the rice manually before packing it into the rice mill. It’s not necessary that you must start a modern rice mill; a small rice mill can also be profitable. If you want to know the exact cost for setting up a rice mill, please do not hesitate to come to us, we will guide you everything from the cost of setting up a rice mill to the layout designing, installation of rice mill and machinery. Modern Complete Rice Milling Plant consists of: Pre-cleaning: removing all impurities and unfilled grains from the paddy De-stoning: separating small stones from the paddy Husking: removing the husk from the paddy Husk aspiration: separating the husk from the brown rice/unhusked paddy Paddy separation: separating the unhusked paddy from the brown rice Whitening: removing all or part of the bran layer and germ from the brown rice Optional items: Polishing: improving the appearance of milled rice by removing remaining bran particles and by polishing the exterior of the milled kernel Shifting: separating small impurities or chips from the milled rice Length grading: separating small and large broken from the head rice Color Sorting: remove bad rice, black rice, yellow rice, half-husked rice, etc Blending: mix head rice with a predetermined amount of broken, as required by the customer Weighing and bagging: preparing milled rice for transport to the customer

Parboiling involves partial boiling of the paddy before milling in order to increase its nontrivial value, to change the texture of cooked rice, and reduce the breakage in milling. Parboiling is done in three steps: Soaking, steaming and drying. Parboiling causes a gelatinization of the starch during the boiling and during cooling the amylase molecules re-associate with each other and form a tightly packed structure. The kernels are harder and appear glassier after the parboiling process. The parboiling process moves micronutrients contained in the bran, which is usually removed in the whitening process in the rice mill, to the endosperm. Parboiled rice is more nutritious than white rice. Parboiling also mends little cracks that might have developed in the endosperm during postharvest processing and therefore head rice recoveries of parboiled rice are higher. Parboiled rice takes less time to cook and is firmer and less sticky when cooked.

There are several factors that determine the final quality of paddy produced at the farm. For best milling results, good quality paddy is needed and mixing of different varieties prior to milling should be avoided. The following factors are important in determining the final quality of paddy rice: Prepare fields uniformly and as level as possible Select the right seeding date and rate Ensure uniform crop nutrition across the field and apply nutrition in time. Keep a uniform water level on the field, and drain the field at the right time prior to harvest. Check the field regularly for pests and control pests when necessary. Keep the fields free of weeds. Harvest at the right grain moisture content and avoid delays in threshing and drying. Clean the grain after harvesting to improve milling output. Dry paddy down to 14% moisture content. Store the paddy at the right Moisture content and protect it from insects, pests. Prepare fields uniformly and as level as possible. Uniform water depth throughout the season will contribute to uniform crop establishment, uniform ripening across the field and, as a results. more consistent moisture content in the grain. Cut (i.e. lower) areas may mature sooner than fill (i.e. higher) areas of a field. Large differences in grain moisture content in rice contribute to fissuring and may accelerate grain spoilage. Select the right seeding date and rate. Seeding date can affect conditions during maturation. High temperatures after flowering can lower the amylose content, increase chalkiness and increase gelatinization temperature. Higher seeding rates will lead to higher plant population, more competition for limited resources, and possibly more lodging and smaller grain size. Lower seeding rates will result in increased tillering with more variation in maturing within the panicle, and higher weed populations. Ensure uniform crop nutrition across the field and apply nutrition in time. Uneven crop nutrition can lead to variation in tillering and tiller maturity across a field, resulting in highly variable grain moisture content at harvest. Nutrition can affect head rice and amylose content. Delayed nutrition may lead to delayed growth and crop maturing, which increases the probability that the crop is affected by adverse weather during harvesting season (typhoon, rain, etc.) Keep a uniform water level on the field, and drain the field at the right time prior to harvest. If rice is exposed to drought stress, the rice plant will abort excess grains and fill fewer grains. Too early drainage prior to harvest may lead to incomplete grain filling and more misshapen kernels. Too late drainage prior to harvest may lead to inability to harvest rice at right moisture content due to field inaccessibility. Check the field regularly for pests and control pests when necessary. Insects such as stink and rice bugs that attack the grain during soft or hard dough stages can result in deformed or spotty grains. The spotty grains arise from infection by bacteria transmitted during feeding. Stemborers cause whiteheads and thus add more unfilled grain to the harvested material. Late applications of pesticides may result in unacceptable pesticide residues in the grain. Keep the fields free of weeds. Heavy weed infestations can reduce grain quality by out-competing the rice for resources (nutrients, sunlight), or by contaminating the rice with weed seeds with high moisture content. The latter can lead to transfer of moisture from wet to dry grain which promotes fissuring. Harvest at the right grain moisture content and avoid delays in threshing and drying. Crops should be cut at 20-25% moisture content (MC) or when 80-85% of the grains are straw colored and the grains in the lower part of the panicle are in the hard doe stage. To avoid fissuring and excessive grain breakage, thresh and dry the grain as soon as possible after cutting. For combine harvesting or threshing with stationary machines, use correct machine settings to avoid mechanical grain damage. Clean the grain after harvesting to improve milling output. The more impurities and unfilled grains are present in the paddy, the lower the milling recovery at the rice mill. Dry paddy down to 14% moisture content. Overdrying (drying below 14% MC) can result in rewetting of grain in humid environments and subsequent grain fissuring and breakage. During the final stages of drying, the drying air temperature should not exceed 43% as higher temperatures will lead to fissuring. To avoid grain discoloration, do not store wet (undried) grain for extensive periods. For best results, the use of mechanical grain dryers for drying wet paddy is recommended. Store the paddy at the right moisture content and protect it from insects, pests. The longer the grain needs to be stored, the lower the required grain MC. Seed stored at MC's higher than 14 % will experience growth of molds. Consider hermetic or sealed storage to reduce insect damage to stored grain.

Customer need to consider the capacity of rice mill plant or consider budget for rice mill plant first. For the target of rice processing and selling white rice to build a medium or small-scale rice processing plant, Medium or large-scale rice mills are available. These can process 10 – 100 tons of rice per day. If the processing plant is small, then Medium or small-scale rice mills will be suitable, and combined rice mills are available. These can process around several tons. If the use is for a family or moveable street vendor, then the small scale or moveable milling machines is the best option.