Miller Magazine Issue: 141 September 2021

76 ARTICLE MILLER / september 2021 Grain is the essential base of human nutrition and feeding in animal husbandry. It needs to be available throughout the processing and can’t be replaced. There- fore it is mandatory to store it during the harvest time when quality and price are at their best. Most mills have invested in bulk storage facilities like silos to simplify the handling for the processing and to maintain the quality of the grain during the storage. However the manage- ment of the storage faces new challenges mostly. They are caused by the nature of grain, the storage environ- ment and the postharvest treatment. Main issues are the high and uneven moisture content, high ambient tem- peratures and relative humidity, heat rise during storage, weevil and mould infestation. All of those cause extra ef- forts, additional cost or reduction in processing efficien- cy which increase by longer storage time. Grain cooling eases the trouble and simplifies the management to one treatment solution for all constrains of grain storage. THE WAY OF GRAIN COOLING The grain cooler is connected to the grain storage by a flexible hose. The treated air is blown into the grain bulk. The air flow passes the grain and removes the heat of the grain. The air becomes humid and warm and ex- its the storage bin through vents at the top. The grain cooling continues until the entire bulk is cooled to the desired temperature, usually in a range of 10 to 18°C de- pending on the storage time. Afterwards the grain cool- er is turned off and the air inlet and vent openings are closed. The cooled grain remains in the silo until it is removed or cooled again if the temperature will increase after several months of storage. Figures of the applica- tion at a vertical silo and warehouse are shown in Figure 1 and 2. THE ACHIEVEMENTS OF GRAIN COOLING FOR GRAIN STORAGE Prevention of Respiration Loss Grain continues to respire after being harvested. Loss- es in freshly harvested grain are primarily caused by its cellular respiration and its heating. The rate of the activi- ty is dependent on the grain’s moisture content and tem- perature as shown in Figure 3 (Jouin, 1964). Respiration becomes exponentially intensive as the temperature “Grain cooling is a comprehensive solution for postharvest management and conservation of a grain bulk. It brings benefits which keep quantity, quality and the processing of a grain in the most economic condition. Its implementation in the warm and humid climates will lead to essential improvement of grain handling, loss reduction and good management practice, which has been proven in moderate climate already for more than 50 years.” Optimizing bulk storage management of grain in silos and warehouses by grain cooling Ralph E. Kolb CEO Frigor Tec GmbH www.frigortec.com Dr. Claus M. Braunbeck Sales Manager Asia Frigor Tec GmbH info@frigortec.de