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Controlling Moisture in Cereal Grain Drying Processes

Controlling Moisture in Cereal Grain Drying Processes
3 May 2024  |
Cereal grains are used to produce animal feeds, flours, cooking oils, fuels, alcohol products, packaging materials and much more. Managing the moisture content of cereal grains is crucial to maximising storage times, maintaining nutritional value and taste, reducing costs and waste and ensuring efficient use during further processing.

The benefits of precise moisture control

  • Grain can be stored safely for longer
  • Minimises the amount of energy required to dry the grain
  • Maintains the nutritional value and taste
  • Reduces harvesting losses such as cracked kernels
  • Reduces dependency on weather conditions for harvesting

Where to measure moisture

Hydronix sensors are used to measure the moisture of the material entering and exiting the dryer. For a system drying material with a reasonably consistent incoming moisture one sensor can be used on the output of the dryer. The sensor’s output can be used as the process variable of a feedback control loop for the dryer.

In Figure 1, Hydro-Mix XT sensors were installed in a re-circulating dryer (locations 4 and 6); using a Hydronix Ducting System to measure the moisture of the grain precisely throughout the batch, allowing the automation system to control the dryer accurately until the required moisture content was achieved.

  1. Wet grain is delivered with higher moisture.
  2. The material is elevated to feed the dryer.
  3. The diverter redirects the material into the dryer or to the silo.
  4. A moisture sensor is installed at the inlet of the dryer. In this location, the sensor enables the drying parameters (feed-forward) to be adjusted based on the material’s moisture.
  5. The material is dried.
  6. A moisture sensor is installed at the output of the dryer to enable precise PID feedback loop control.
  7. The material is elevated.
  8. Depending on the measured moisture level, the material is either diverted to the silo for storage or recirculated to the dryer for further drying.

Result after installing the sensor

Although a well-calibrated system will achieve accuracies better than ±0.5%, the results were obtained from the output of a dryer processing barley, where an average accuracy of ±0.17% was achieved.

The moisture range was limited as the dryer controller was operating to maintain a target slightly lower than 12.5% to make the barley suitable for long-term storage.


Drying grain to a consistent target requires highly accurate sensors that can provide precise and repeatable measurements, resulting in a consistent product a reduction in spoiled or wasted material and better efficiency.

Hydronix sensors, such as the Hydro-Mix XT and Hydro-Mix XT-EX offer a purpose built, robust and durable solution for grain drying and processing applications. These sensors can significantly increase profitability through waste reduction, yield maximisation and efficient use of energy.

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Hydronix is the world’s leading manufacturer of digital microwave sensors for online moisture measurement. Hydronix was established in 1982 and pioneered the digital microwave moisture measurement technique. Hydronix has a global presence, selling to over...

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