Moisture Control in Grain Conditioning/Tempering
Whilst processing grain, moisture is often added during grain conditioning or tempering steps to improve process efficiency, product quality, and shelf life.
Applications include processing rice, wheat, corn and other cereal grains for final product, flour or feed production, and other food production processes, such as chopping and flaking products before further processing.
Benefits of Moisture Control
- Improved milling quality – Proper moisture softens the grain, reducing breakage and increasing flour yield.
- Consistent product quality – Uniform moisture ensures even processing and better texture in the end products.
- Reduced energy consumption – Optimised moisture levels help avoid over-drying or excess steaming, reducing energy use.
- Minimised spoilage and mould – Controlling moisture prevents conditions that promote fungal growth during storage.
- Better storage stability – Properly conditioned grain is less likely to crack or go rancid over time.
- Increased processing efficiency and reduced process downtime – Machines run more smoothly and with less wear when grain moisture is in the ideal range.
Where to Measure Moisture?
There are two common measurement locations:
- Conditioner input: Measuring the moisture before entering the conditioner allows the control system to calculate the correct water to add in the tempering step.
- Conditioner output: Measuring the moisture leaving the conditioner enables a feedback loop to provide consistent product quality and enables adjustment for variations in the process.
Measuring and controlling the moisture ensures the material is not too wet or dry. This optimises the product for the following process stages.
Recommended Installations
Ducting System
The sensor is mounted in a ducting system, ensuring consistent flow and speed. The sensor can be mounted vertically or at an angle.
Screw conveyor
The sensor is mounted in the belly of the conveyor, at 30° from the underside and ideally before the sampling point.
Industry Expert Opinions on Moisture Control
„Tempering is a process in which the grains are wetted long enough so that water permeates the bran. This process of hydration makes the bran less brittle and helps loosen it so it can separate into large pieces, which are more easily sifted away from the flour when the grains are milled. Water also mellows the endosperm, making it easier on the grinders.“
Rabbi Tzvi Rosen (Winter 2024)1
„Professional millers know that the cleaning process of wheat is important for wheat flour milling. One of the key steps is the wheat moisture conditioning process before milling… The wheat moisture conditioning process adds water to the wheat… until the added water penetrates the wheat kernel and optimal moisture distribution is achieved, to improve the physical, biochemical, and processing properties of the wheat for optimal flour milling process.“
ABC Machinery2
Conclusion
Controlling the moisture before and after conditioning grains is vital. It improves their quality by providing a consistent product, reducing spoilage and mould, optimising processing, and increasing shelf life.
- Rabbi Tzvi Rosen (winter 2024). Controlling Your Temper
https://www.star-k.org/articles/kashrus-kurrents/13298/controlling-your-temper/ ↩︎ - bestflourmill.com, Wheat Conditioning and Tempering Process-Provide Optimum Moisture for Flour Milling https://www.bestflourmill.com/flour-mill-processing/wheat-moisture-conditioning-tempering-process.html ↩︎
