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Accuracy and consistency of Moisture Meters

Accurate moisture meters
Sianr Moisture Meters

Accurate moisture measurement is critical at harvest time and throughout drying and storage. It makes financial sense to use a moisture meter that has a track record for providing consistent, accurate and reliable grain readings.

At Sinar we take your moisture seriously -

The following is meant for general guidance only.

Different makes of moisture meter have different modes of operation, but these general points usually hold true for most makes.

Graph of grain moisture
Grain Moisture Content

Follow manufacturer’s guidelines.

Ensure calibration and maintenance is undertaken each year (ideally, by manufacturer). Always follow usage instructions. Many farmers do not get their machines serviced and checked annually. Whilst it is possible for a meter to give incorrect results due to calibration drift and error, more often problems result from non-representative sampling, incorrect operation and poor maintenance.

Keep your meter in tip top condition.

If the meter is not going to be used for a long time, take the battery out. This will increase the life of the battery and reduces the risk of leaking. You’d be surprised how many moisture meters we get in for repair because they won’t switch on and just need a new battery.

Keep the instrument clean and dry – moisture meters really don’t like water! Clean the measurement cell with a dry, clean, lint free cloth.

Don’t use cleaning agents or water as this will impede the meter’s electrical characteristics.

Keep your Sinar Moisture Meter Accurate, consistent.

Testing new crop and off the dryer.

New crop straight off the field is a rapidly changing sample. It is a living, respiring seed that will change chemical & physical characteristics over the next few days/weeks while it starts to become dormant. Moisture readings at this time can be tricky as the moisture content can change very rapidly as surface moisture & bound moisture in the seed change.

This is also the case fresh off the dryer.

The best thing to do is to test, test & test again. The more information the better. Make sure the moisture meter is picking up the sample temperature accurately and test large amounts of sample – scoop up a bucketful of clean grain, mix thoroughly and test several different samples from the bucket. Be careful not to measure admix as this will change the meter reading. Similarly, a high concentration of ‘greens’ in the sample will also skew the result.

Use tested calibration samples.

Calibration samples can be obtained from Sinar Technology or sometimes from mills and grain stores. These should be used regularly to check that your meter is not varying from test to test.

Keep calibration check samples in a watertight container, with minimum free air space, at an even air temperature.

Mix each sample thoroughly before testing. Repeat testing of the same sample should give meter readings within ±0.3%.

A friendly mill or grain store, particularly if you’re sending your crop to them, should be happy to test a few of your initial samples which can then be used as calibration checks for your on-farm moisture meters.

Double check the temperature.

Most ‘quality’ moisture meters are temperature compensated. This means they take the temperature of the sample into account when calculating the moisture content. It is critical that you allow the moisture meter some time to arrive at the temperature of the sample so that the calculation is as accurate as possible.

This is particularly important when testing warm or cold grain – off a drier or in winter when using blowers.

On a Sinar device there is a temperature button so that you can manually check the grain sample temperature and make sure that it isn’t varying during testing.

Sinar Moisture Meter
Sinar GrainPro

Only use moisture probes for rapid assessments.

Use probes to rapidly monitor the moisture content of grain within a bulk, but not in place of meters to assess moisture content of samples. Although generally not as accurate as conventional moisture meters, probes give consistent and reliable results.

Allow a safety margin.

A moisture meter is a scientific instrument. Like all scientific instrumentation it has an operating range, measurement limits & a margin of error.

Most moisture meters are set up at the crucial ‘money making’ point in the measurement range – for Wheat 15%. This is where the moisture meter will be at its most accurate. As you move away from this point, either drier or wetter there will be a greater margin of error. Please look at the documentation provided with your moisture meter or talk with the manufacturer.

It is prudent to treat meter readings conservatively. Errors are frequently ±0.5% and can be greater in very wet, very dry or freshly harvested grain. Farmers who allow a 0.5% safety margin are far less likely to have claims for excess moisture.

Don’t forget for any other questions.

Moisture Meter, Accuracy, Consistency, Sinar


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