Miller Magazine Issue: 150 June 2022

72 COVER STORY MILLER / JUNE 2022 storage life and preserve their yield, millers choose to store their grains into silos. Silos are high-capacity com- mercial or industrial structures that are used for perma- nent grain storage. Grain storage in metallic grain silos is the most cost-ef- fective, economical and long-term storage system. Grains in a silo can be monitored in real-time for its quality and quantity very efficiently. Spillage and grain spoilage are minimum in silo storage system. Other advantages of stor- ing grains in a silo include high-speed handling of grains, effective fumigation, less dependence on labour and very less operation cost. Hence buying grain silos to store grains is a big finan- cial and strategic decision and it must be taken with a full understanding of metallic silos and its accessories. While setting up specifications for grain silos the following points must always be considered: •Flat bottom or hopper bottom silos •Design considerations •Corrugation profiles •Design specification of steel sheets •Material of construction of metal coated steel sheets •Grade of steel and thickness of sheets •Galvanization standards •Fasteners •Aeration and perforated floor •Vents and roof exhausters •Temperature monitoring system •Fumigation system Modern grain storage or scientific storage means real-time monitoring of quality and quantity of grains. There are many methodologies of modern grain stor- age, and all have advantages and disadvantages. The concept of storing grains in silos is most acceptable for long-term grain storage as it is scientific and ensures rapid handling of grains. Silos are not static ; it is dynamic equipment and must be operated properly to maintain the grain quality inside the silo. Aeration, ventilation and fumigation should be sized properly so that the environment inside the silo can be controlled to maintain the grain quality. Grains are hygroscopic in nature. Grains absorb or desorb moisture based on temperature and relative hu- midity of air surrounding them and continue to absorb or desorb moisture until it attains equilibrium with the surrounding air. This final moisture content of the grain is called Equilibrium Moisture Content (EMC). This EMC value is different for different grains based on RH and the Temperature of the surrounding air. Understanding the EMC concept of grains is very important to under- stand how grains will behave in various temperature and relative humidity conditions. In general, relative hu- midity of 65% or less is considered safe for the storage of grains. The storage period of grains depends upon the moisture content of grains. As a rule of thumb 9% to 13%, moisture content of grains may give a storage life of 8-11 months, however, there still may be some infes- tation problems, which have to be tackled with effective