Harvest is the culmination of a year of hard work. Every hectare planted and every dollar invested translates into grain yield. Once harvested, dried grain loses moisture and weight. This leads to a phenomenon that every producer is familiar with: shrinkage. This term refers to the direct relationship between volume, weight, and moisture content. See how grain moisture affects your profitability.

Two elements make up grain:

  • Dry matter (DM): this includes starch, proteins, lipids, and fibre.
  • Water (H₂O): this is the variable water fraction that determines the moisture content.
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    Weight equation:

    Total weight = Dry matter weight + Water weight

     

    Example: 100 kg of corn grain with 15% moisture content contains:

    • 85 kg of dry matter

    • 15 kg of water

    The effect of moisture content on weight

    The market does not pay for water content, only for dry matter. Therefore, two batches containing the same amount of dry matter but with different moisture contents will have different weights. This means they will have different commercial values.

    • Batch A: 100 kg at 15% → 85 kg of dry matter.

    • Batch B: 100 kg at 17% → 83 kg of dry matter.

    Visually, the gross weight appears to be the same, but the actual dry matter value is lower in batch B. The buyer therefore adjusts the price using a shrinkage factor.

    The effect of moisture content on volume

    One hectoliter of first-quality corn at 14.5% moisture content weighs approximately 72 kg. The more moisture the grain contains, the lower the weight per hectoliter, because water is lighter than cornstarch.

    Thus:

    • Corn at 13.5% → approximately 73.5 kg/hL

    • Corn at 14.5% → 72 kg/hL (reference)

    • Corn at 17% → approximately 70 kg/hL

    Quite rightly, when corn is dried, it gains weight. This means that #3 grade corn may be reclassified as #2 grade due to the increase in density during the drying process. 

    But be careful! A grain that has not reached full maturity may lose weight, especially if it is heated to a high temperature.

    Find more information and expert advice on our blog

    Mathieu Phaneuf, président-fondateur Agrilog

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