Which moisture meter is right for you?
- isabelle7349
- 4 days ago
- 5 min read
Updated: 3 days ago
What are the key factors to consider when choosing a moisture meter? Whether for corn, soy or wheat, accurate moisture measurement is essential, both to ensure grain preservation and to optimize the commercial value of your harvest.
Moisture meters are essential tools for your grain center. There are several types, each with its own advantages, limitations and technologies. Let's explore the main categories of moisture meters, how they work, and a comparison of models offered by recognized manufacturers: Perten, Dickey-John, Foss, Seedburo, Labtronics 919, Prairie Grain Analyzer, Shore et Agratronix.
This guide will help you:
Understand the different technologies used in moisture meters.
Choose a model suited to your needs.
Compare the main models on the market in terms of their usefulness, accuracy and cost of acquisition.
Types of moisture meter
Resistive moisture meters (conductivity measurement)
Principle: Resistive moisture meters, also known as electrical conductivity moisture meters, measure the electrical resistance of a grain sample placed between two metal electrodes. Moisture influences this conductivity. In other words, the more water a grain contains, the more easily it conducts electricity. The less moisture, the greater the resistance. The device converts this resistance into an estimate of the moisture percentage, according to calibrated tables.
Limitation: Grain moisture must be uniform throughout the grain if a good reading is to be obtained. This means that tests in the field, or at the dryer outlet, will be less reliable.
Model examples: Agratronix MT-PRO, Dickey-john Mini GAC and Mini GAC Plus, Shore 920, Seedburo 919, Dimo's Labtronics 919
Advantages:
Economical
Portable for most
Easy to use
Disadvantages:
Low accuracy (0.5% to 1.0%)
Range of use limited by temperature
Moisture reading influenced by temperature
Less reliable with very dry, very moist or non-uniform grains
Some models cannot be calibrated after purchase
Capacitive (or dielectric) moisture meters
Principle: Capacitive moisture meters, also known as dielectric moisture meters, measure grain moisture by evaluating the dielectric permittivity of the sample. In simple terms:
The grain is placed in a measuring chamber between two electrodes (2 plates)
An electric field is applied to it
The device measures how the grain modifies this field
The grain's moisture strongly influences this reaction, enabling the moisture meter to deduce it.
📌 The moister the grain, the greater its capacity to store an electric charge.
Limitation: The latest capacitive moisture meters use weighing to adjust the moisture reading according to grain density. It is therefore important to follow up with the equipment, with a recognized specialist, to maintain optimal calibration.
Model example: Perten AM5200-A, Dickey-john GAC (2500, 2700-AGRI, 2700-UGMA), FOSS GAC 2500-C, Grain Prairie Analyzer
Advantages:
Very fast readout (between 10 and 30 seconds)
Very high accuracy (0.1 to 0.5%)
Measures moisture, temperature and specific weight
Commercial, stationary and very accurate devices
Well suited for intensive use
Disadvantages :
Sensitive to temperature variations
Requires a controlled, clean environment
Requires sporadic, specialized monitoring and calibration
High acquisition cost (between 6,000 and 15,000 CAD)
NIR (Near infrared) moisture meters
Principle: NIR (Near Infrared) moisture meters use advanced spectroscopic technology to measure moisture and other grain properties. Unlike resistive or capacitive moisture meters, NIR moisture meters analyze the light reflected by the grain at different wavelengths to deduce its composition.
Limitation: This advanced technology and its high cost limit its use for commercial purposes.
Example models: Perten IM9500, Perten DA 7250, FOSS Infratec 1241.
Advantages:
Fast readout (between 30 and 60 seconds)
Very high accuracy (0.1%)
Can measure moisture, temperature, specific weight, protein, oil, ash and other readings depending on the model
Commercial, stationary and highly accurate devices
Accepted as a reference in many international protocols
Disadvantages:
Very high acquisition cost (30,000 to 50,000 CAD)
Requires specialized maintenance and calibration
Designed for stationary use and a controlled environment
Some models require training for interpretation of results and optimal use.
Sample and instrument must be at a stable ambient temperature for reliable results.
Laboratory drying oven methods
Principle: Oven (or laboratory drying) moisture meters are the official reference for grain moisture determination in many grading standards (e.g. ISO, AACC, GSC). In this method, the grain is heated and weighed before and after drying; the loss in mass corresponds to the moisture.
How does a moisture meter work?
Initial weighing of the grain sample
Controlled heating to a precise temperature (often between 103°C and 130°C)
Evaporation of the water contained in the grain
Final weighing once drying is complete
Calculation of water mass loss, expressed as a percentage
👉 This method can be carried out using a conventional oven or a halogen moisture meter (faster).
Limitation: Although extremely accurate, this type of moisture meter is limited to laboratory purposes, or for equipment calibration. Like moisture meters.
Advantages:
Optimum accuracy (0.01% to 0.001%)
Official reference method
Used to classify test samples or measuring equipment
Disadvantages:
Very long measurement time (15 to 40 minutes).
Destruction of the sample during testing
Requires a rigorous test protocol to obtain a reliable and accurate result
High acquisition cost for drying ovens (CAD 2,500 to 6,000)
Very high acquisition cost for halogen drying ovens (CAD 6,000 to 10,000)
5 Tips for better readings
Several factors can influence the accuracy of your tests. If you want more reliable readings, here are 5 tips to help you:
Keep your moisture meter in a safe, controlled and clean environment
Maintenance: Keep your equipment clean, and clean it regularly
Follow-up and calibration: Compare your results with a reliable source, and calibrate if necessary.
Representative sampling: 5 kg sample, mix well without impurities.
Perform several measurements (3 to 5 tests): For each sample and calculate the average
Manufacturer and model comparison
Recommendations
Limited budget (1000 CAD): Portable resistive moisture meters can be used to carry out assessment tests. For greater accuracy, run several tests on your sample and compare with a reliable source. Such as a commercial grain center with a moisture meter like Perten's AM5200-A or Dickey-john's GAC-UGMA.
Regular farm use (2000 CAD): opt for a fixed resistive moisture meter. Some models are sturdier, more reliable and will give you a more accurate reading. If you need a moisture meter to monitor your dryer, avoid portable models.
For grain centers (6000 to 8000 CAD): opt for a moisture meter with capacitive technology. The accuracy you'll achieve pays off when you're dealing with large volumes of grain. Because 1% moisture is 1% mass, a 0.1% inaccuracy on 10,000 tons represents 10 tons of grain value. Your moisture meter will quickly pay for itself.
Elevator or terminal (8000 to 15000 CAD): Choose a moisture meter with commercial capacitive technology. In addition, be sure to have your moisture meter inspected regularly. Intensive use requires more frequent maintenance. Once again, a loss of accuracy represents a lot of money.
Food industry (30,000 CAD +): Infrared (NIR) technologies are specifically designed for this type of application. Only this equipment will give you all the measurements you're looking for.
In conclusion
A moisture meter is not just a measuring tool, but a guarantor of grading compliance, storage security and optimal income at the time of sale. An indispensable ally in making informed decisions, avoiding downgrades and maximizing the profitability of your harvest.
Before making your choice, it's important to consider a number of factors: the parameters to be measured, the number of tests to be performed, the frequency of use and, finally, the profitability of the equipment.
Equipment from Perten, Foss and Dickey-John offers high performance, particularly in the context of official grading or export. For everyday needs on the farm, models such as AgraTronix, Shore, Seedburo and Prairie Grain Analyzer offer excellent value for money.
But always remember: a good sampling method and test protocol are just as important!
Useful links:
Acknowledgements: We would like to thank Precision Calibration and Equipment for their contribution to this blog.