Miller Magazine Issue: 139 July 2021

53 COVER STORY MILLER / july 2021 THE NATURE OF THE AERATION SYSTEM There is always the need of storing a certain commodity, for an amount of time in a particular kind of environment. The response to this need comes from literature and agri- cultural science, which provides safe storage charts. With the chart shown, we can compare the commodity (in this case wheat - Fig. 6) and the safe storage time, with its tem- perature and the moisture contained. Therefore, we know there is a need for a certain temperature and moisture sur- rounding our seed during storage. Also, aeration avoids natural migrations which can cause the moisture to concentrate or condense in some regions of the bin and it is interesting to see how this behavior is mirrored. In warmer regions the moisture usually migrates to the bottom center and the central well gets stuck, (Fig. 3) while in cold regions the moisture tends to migrate to the top pile making crusts and germinations. The hygroscopic nature of grains A certain temperature and a certain moisture for our seed can be successfully obtained by knowing that the grain is hygroscopic. Hygroscopic means that the kernel can take up or release moisture from or to the atmosphere in which it is placed. Wood, fertilizers and even sugar are examples of hygroscopic commodities. Therefore, the technology and the knowledge today allows us not only to control the grain temperature, but also the grain moisture, thanks to the development of EMC (equilibrium moisture content) charts (Fig. 4 is an example). This can be developed spe- cifically for your commodity at any of our AGI Labs. Inner environment First, we need to know there is an inner environment in (Fig. 2) our storages which involves: the grain itself, air and water vapors, heat and moisture, and insects and mites. These factors are all interconnected to each other. Figure 1 Figure 2 Figure 3