New Tool Helps Manage Grain Moisture Content

clemson moisture calculator app
Corn harvest is underway and Clemson University has a new app to help farmers when making decisions related to storing or field drying grain crops — photo courtesy Clemson University

Developed by Clemson’s Department of Agricultural Sciences and Precision Agriculture group, a new calculator is available to help farmers optimize moisture content of stored grain and evaluate field drying.

Equilibrium Moisture Content (EMC) is the moisture grain will attain if exposed to a specific relative humidity and temperature for a given time. EMC calculations are used to determine the best drying conditions.

Clemson agricultural mechanization and business program assistant professor Aaron Turner says, “Knowing the EMC is useful for estimating the moisture content of grain in storage, determining the lowest moisture content that can be achieved for given conditions and analyzing drying processes.”

A Goal Of Preserving Quality

EMC can be used as an indicator of how grain moisture will change. If EMC is lower than grain moisture content, drying will occur. If EMC is higher, rewetting occurs, although much slower than drying.

The calculator predicts how EMC will change using the five-day forecast from This is useful for drying decisions where fans and air are used to condition the grain.

“The goal is to cool and dry the grain to reach safe storage conditions and to preserve quality,” Turner says. “When using natural air drying, heat and moisture are transferred from the grain to the air being blown through the bin.”

Traditionally, farmers have been advised to continuously run fans until the drying front moves all the way through the grain. But recent research has shown intermittent fan operation works in some situations.

“This prevents warming the grain, rewetting and can help save electricity. The tool helps identify periods when the air would be productive to either cool or dry grain.”

Free, Web-based Calculators

This free web-based calculator can be found at

To calculate EMC for a single set of conditions, four inputs are required — temperature, relative humidity, crop and model. Several models have been proposed to represent this relationship, and the calculator allows users to select between them and see changes in the results. Farmers who don’t have a preference as to the model they use should use the default composite option.

The EMC calculator is one of several free, web-based apps from Clemson Precision Agriculture accessible from most devices with a web browser. These apps can be found at

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