Stages of Oat Processing and By-Product Generation Stage Process By-Products Details I Harvesting and threshing Oat straw, chaff, and screenings Straw comes from the plant stalks; chaff and screenings are separated during threshing and cleaning. II Cleaning and grading Dust, foreign material, immature grains, and broken kernels These materials are removed before the grain enters the main processing line. III Dehulling Oat hulls The tough outer hull is removed to obtain oat groats, the edible kernel. IV Groat processing and milling Oat bran, broken groats, fines, and some germ-rich fractions The fractions depend on whether the groats are cut, rolled, milled, or separated into different particle sizes. V Food manufacturing Broken flakes, fines, off-specification material, and wet-process residues These can be redirected to food ingredients, animal feed, or other recovery routes, subject to quality requirements. For a simplified mass balance, the following ranges illustrate how 1,000 kg of cleaned whole oats can be divided during processing. Typical percentage of each fraction Fraction Approximate proportion of incoming oats Quantity per 1,000 kg Oat hulls 20–30% 200–300 kg Dehulled oat groats 68–75% 680–750 kg Other losses and separated material Variable Balance Source: ScienceDirect and FoodDirect These are indicative ranges, not fixed yields. Published sources report hull fractions around 20–25%, with some oat varieties reaching 30–36%. The groat recovery depends on grain quality and dehulling efficiency. The ranges above should not be combined as exact figures for a single production batch. A simplified processing pattern is illustrated here: Bran and fines are secondary fractions from the groats and should not be added again to the original whole-oat mass balance. Share this article