How “Representative” is Your Moisture Sample?

Posted on November 8, 2013 Updated on September 30, 2013

Taking a moisture sample when you are drying may seem like an easy process, and in some ways, it is. But it can also give you a false sense of having a very precise result.

Take the case of when you go to the dryer and take a grab sample. You take the sample back to the bench top tester and get a digital readout. Let us say this time the readout is 15.2 percent… So, what does this number mean?

It does not mean that all the grain coming out of the dryer is at 15.2 percent. One way to easily see this is to watch the continuous readout from the Dryer Master, which can move up and down a few tenths of a point over a few minutes.

Another way to see this is to take three samples three or four minutes apart and see if the three samples give you the same reading. In most cases, they will not be exactly the same. The questions begin: Which one is right, and which one should you be using to make any adjustments to your drying?

Small differences are actually a very normal part of sampling. It is all but impossible to get an exact reading that covers all the grain exiting the dryer. There is simply too much inherent variation. This also explains why you may see small differences with your readings and the Dryer Master readings when you are doing calibrations.

That brings us to one of the benefits of Dryer Master. The DM510 continually (6 times a second) samples the grain moisture at the outlet of the dryer, and at the inlet too, so you always have a good idea of the moisture levels going into and coming out of the dryer. The Dryer Master is also aware of these variations and takes them into account when making its control (discharge rate) adjustments.