Figure 2. Examples of moisture testers designed for on-farm use. Other products are also available, including refurbished commercial testers.
Grain dryers with manual settings need to be checked frequently with a good moisture tester to achieve the desired moisture levels. Computer-controlled drying systems rely on a moisture tester as a standard to calibrate sensors reading wet grain in and dry grain out. The amount of investment justified in precision drying systems and storage aeration will depend on the number of bushels that can be run through the operation.
Too wet or too dry? If growers had the choice of delivering grain that is 1 point too wet or 1 point too dry, they should choose "too wet," as the economics are overwhelmingly on their side. Delivering grain too dry results in losing all of the weight represented by the moisture differential. Delivering grain too wet incurs drying costs (some of which would have been spent to dry the grain on-farm) and shrink, but "weight" per se will not be lost.
Overdrying grain: Grain stored long term on the farm may be significantly lower in moisture than the maximum allowed by the grain buyer. In fact, even grain stored short term may be lower than required for some uses such as wet milling. Each end use (dry-grind ethanol, wet milling, long-term storage, etc), may have a different moisture allowance, and knowing that number is the first step in meeting it.
Figure 3. Various grain buyers may have different grain moisture requirements, depending on grain use and expected storage time.
If grain is too dry, some growers may have the option of blending or aerating the grain to adjust it to the maximum moisture allowed (up to 15.5%). The resulting moisture content of a uniform blend of 2 grain sources is the weighted average of the 2 grain moistures.
Increasing grain moisture content by aeration is usually only possible with very high airflow rates such as those common in natural air drying systems. Even then, successful moisture adjustment may require electronic control systems that run the fans when ambient temperature and relative humidity conditions dictate. In bins with limited fan capacity, increasing grain moisture may require months to accomplish, or may be impossible. In such cases, preventing overdrying of grain is even more important.
Grain drying and storage concerns, like other areas of production and management, can provide added opportunity for those willing to fine-tune their operations with an investment of time and/or capital