Miller Magazine Issue 108 / December 2018

82 MILLER / DECEMBER 2018 “There is a misconception, very widespread, that one should not clean, dry or aerate the grain because it will lose weight. If there is one error that brings the chaos to a grain elevator it is that.” First of all, I have to warn you that I am fami- liar only with the grain trading rules of Uruguay and Argentina. In other countries there are di erent rules and they may be applied di erently. Anyway, I think the procedure that I will descri- be is reasonable and can be understood by any vendor or client in case of disagreement. There is a misconception, very widespread, that one should not clean, dry or aerate the grain because it will lose weight. If there is one error that brings the chaos to a grain elevator it is that. All grain that enters or exits a grain elevator has some content of water and dirt. Water in grain is called moisture, and it is the sum of wa- ter on the surface of the grain, in its pores, and also that chemically bonded to other substan- ces. The water that may be dried of grain is of the first two types. Dirt in grain is called foreign matter. It is the sum of things that shouldn’t be there. For example, bolts, sticks, bags, husks, actual soil dirt, fragments of grain, etc. Foreign matter has almost no commercial value, dificults aeration, may cause fires in dryers, may break processing and conveying equipment, and pol- lutes the environment. The ideal moisture con- tent in grain depends on the specific grain and the final use. The ideal foreign matter content is zero, but it is not actually achievable, because every time you move grain it breaks a little. Many people resist drying or cleaning grain because they think the weight they lose is tons of grain that they could have sold. They don’t realize that there are commercial standards in every country specifying acceptable contents of moisture and foreign matter. Each percentage point that you go over the limit, the buyer will charge you, making a discount on the price they pay. This discount amounts exactly to the tons of water and dirt you are trying to sell him. In Are you afraid of losing weight? Prof. Gustavo Sosa Industrial Mechanical Engineer Licensed Grain Inspector MBA Project Management SOSA – Engineering Consultants Email: ing.gustavo.sosa@gmail.com