If you are using a portable grain moisture tester
, first make sure the battery is charged. A low battery can cause inaccurate readings. The battery should be removed during the tester's long, idle periods to prevent damage from leakage, and replaced at least once per year.
Be sure that you read and understand the manufacturer's instructions. Pay particular attention to the tester's temperature compensation method. Grain temperature can have a large effect on moisture readings. Some testers have automatic temperature compensation, some compensate only after you push a button, and others require that you measure grain temperature, then add or subtract a correction factor to the moisture reading.
Cold grain temperatures will usually cause low readings, unless moisture has condensed on the surface. With condensed surface moisture, electronic testers will usually give high readings. Moisture condensation occurs when cold grain is removed from storage on a warm, humid day, or when cold samples are taken into a warm, humid room. Cold grain should be warmed in a sealed container before making moisture tests.
Testing hot grain from a dryer is difficult, too. Electronic testers tend to understate the moisture content of hot or rapidly cooled grain. Grain also loses moisture as it cools. To get the actual moisture content of hot grain, let it cool slowly in a sealed container before testing.
Remember, all grain moisture testers show some variability. Different readings can be obtained when the same sample is tested repeatedly. Because of this, you should test each sample at least three times and average the results.