Moisture calibration and conversion table updates for moisture meters

Moisture is one of the most important components of grain. It can affect the quality, test weight and appearance of grain. Grain that is too moist is susceptible to deterioration which affects the stability, quality and safety of foods. Moisture is an economically important quality factor to the producer, grain company, processor and consumer.

Moisture content in grain is typically measured using moisture meters which employ indirect methods to obtain results. To ensure accurate measurements, moisture meters are calibrated against official oven drying methods. Moisture calibrations align the meter’s measurements to the official method result.

The Canadian Grain Commission determines the moisture content of grain with Unified Grain Moisture Algorithm (UGMA) moisture meters. UGMA models include the Perten (PerkinElmer) AM 5200-A and the DICKEY-john GAC 2500-INTL and GAC 2700-INTL. The Canadian Grain Commission also monitors and updates conversion tables for the model 919/3.5” moisture meter as it is still in operation in the grain sector.

The Canadian Grain Commission verifies the accuracy of existing moisture calibrations for the UGMA moisture meters and moisture conversion tables for the model 919/3.5” moisture meter using samples obtained from the annual harvest. Updates to calibrations and conversion tables are made when the difference between meter results and official method results exceed tolerances for the most recent 3 years (minimum) of data for each grain type. Calibration development for both model 919 and UGMA-type moisture meters is based on best-fit regressions to the official method results. In choosing the best calibration, the overall fit of the regression is evaluated, not specific samples.

The Canadian Grain Commission will apply the moisture calibration and conversion table updates listed below to all Canadian Grain Commission instruments effective July 1, 2025. The Canadian Grain Commission recommends the grain sector implements these updates to ensure accurate measurements and fair transactions.

Moisture calibration updates and conversion table effective July 1, 2025

Model 919/3.5" moisture meter
Commodity Reason for change New chart comparison to current chart at 22°C New dial reading range for 11 to 30⁰C New moisture range for 11 to 30⁰C
Peas Current chart overestimates moisture content
  • Predicts 0.0 to 0.2% lower moisture
 5.0 to 69.5 7.7 to 24.1%
Wheat, Canada Western Soft White Spring Current chart overestimates moisture content
  • Predicts 0.0 to 0.3% lower moisture
 15.0 to 69.5 7.4 to 21.1%
Models AM 5200‑A (Perten) and GAC 2500 / GAC 2700 (DICKEY-john)
Commodity Model Reason for change Implications of calibration change *
Bean, Canada Cranberry AM 5200‑A Current calibration has a bias greater than 0.2% over the last five years Within the moisture range of 11.8 to 20.5% for the 2020 to 2024 crop years, the average differences at 22°C are the following:
  • 0.0% ± 0.10 between UGMA models (N=19)
  • 0.1% ± 0.31 between model 919/3.5” (No. 2, 2006) and model AM 5200-A (N=19)
GAC 2500 / GAC 2700 Current calibration has a bias greater than 0.2% over the last five years
Domestic Mustard Seed, Brown, Canada AM 5200‑A Second order density correction applied Within the moisture range of 4.7 to 12.3% (5.4 to 12.3% model 919/3.5”) for the 2020 to 2024 crop years, the average differences at 22°C are the following:
  • 0.0% ± 0.10 between UGMA models (N=132)
  • 0.0% ± 0.25 between model 919/3.5” (No. 11, 2007) and model AM 5200-A (N=128)
GAC 2500 / GAC 2700 Second order density correction applied
Domestic Mustard Seed, Yellow, Canada AM 5200‑A Second order density applied Within the moisture range of 4.9 to 14.3% (6.2 to 13.5% model 919/3.5”) for the 2020 to 2024 crop years, the average differences at 22°C are the following:
  • 0.0% ± 0.08 between UGMA models (N=209)
  • 0.2% ± 0.22 between model 919/3.5” (No. 9, 2007) and model AM 5200-A (N=205)
GAC 2500 / GAC 2700 Second order density applied
Wheat, Canada Eastern Soft Red Winter AM 5200‑A Current calibration has a bias greater than 0.2% over the last five years Within the moisture range of 10.4 to 18.8% for the 2020 to 2024 crop year, the average differences at 22°C are the following:
  • 0.0% ± 0.06 between UGMA models (N=308)
  • 0.1% ± 0.16 between model 919/3.5” (No. 3, 2024) and model AM 5200-A (N=308)
Wheat, Canada Eastern White Winter AM 5200‑A Current calibration has a bias greater than 0.2% over the last five years Within the moisture range of 12.3 to 17.8% for the 2020 to 2024 crop years, the average differences at 22°C are the following:
  • 0.0% ± 0.06 between UGMA models (N=147)
  • 0.1% ± 0.22 between model 919/3.5” (No. 6, 2019) and model AM 5200-A (N=147)
Wheat, Canada Western Amber Durum

Wheat, Canada Eastern Amber Durum		 AM 5200‑A Base calibration change Within the moisture range of 8.8 to 20.5% for the 2020 to 2024 crop years, the average differences at 22°C are the following:
  • 0.0% ± 0.05 between UGMA models (N=215)
  • 0.1% ± 0.17 between model 919/3.5” (No. 5, 2020) and model AM 5200-A (N=215)
GAC 2500 / GAC 2700 Base calibration change
Wheat, Canada Western Soft White Spring AM 5200‑A Current calibration has a bias greater than 0.2% over the last five years Within the moisture range of 9.4% to 17.0% for the 2020 to 2024 crop years, the average differences at 22°C are the following:
  • 0.0% ± 0.06 between UGMA models (N=213)
  • 0.0% ± 0.17 between model 919/3.5” (No. 6, 2025) and model AM 5200-A (N=213)

*N=Number of samples tested

Calibration files and installation instructions for UGMA moisture meters are available for download on each manufacturer’s website.

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