Stored Grain Management: Storing Grain In Bins

Excerpt from Agronomy Guide for Field Crops (Chapter 10)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Introduction
2. Good Bin Management Suggestions
   • Why Aerate Grain in Bins
   • Basics of Aeration
   • Time Required for Aeration Front to Move Through Grain - Table 10-1
3. Grain Storage Monitoring
   • Monthly Bin Monitoring Checklist
4. Updates on Stored Grain Management: Storing Grain in Bins
5. Related links...

Introduction

Maintaining grain in good condition in storage requires careful, routine inspection and good storage practices. Good storage practices consist of more than simply putting good-quality grain into a weatherproof container.

The quality of the grain loaded into storage is the best it will ever be. Over time, the quality of this grain will only decrease and seldom, if ever, improve. The goal is to maintain grain quality at the same level as when the grain went into the bin.

Good Bin Management Suggestions

• Treat empty bins to control any stored grain pests that may be living in cracks, crevices and below the aeration floor.
• Clean any grain going into a bin.
• Remove fines and other foreign material to reduce air flow restrictions and possibly reduce the risk of spoilage.
• Core a bin (augur out some grain) after filling to establish the flow funnel and redistribute the fines, even if the removed material is put back into the same bin.
• Install a manometer in the air plenum below the aeration floor to monitor the static pressure of the air moved by the fan. For information on how to build a manometer, see Appendix I, Home-Built Manometer.
• Use the static pressure to determine the air flow of the fan, from the fan performance curve.
• Tightly cover aeration fan inlets when not in use, to prevent unintentional air movement through the grain.

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Why Aerate Grain in Bins

The aeration of grain stored in a bin:

• removes field heat at the time of harvest or cools grain from a dryer
• brings the whole mass to a uniform temperature
• removes moisture that has respired from the stored grain as a result of temperature changes caused by the outside air

As bin surfaces are warmed or cooled by the sun or outside air, air currents start to move by convection in the grain mass. Moisture from the grain is carried by these convective air cells and condenses on colder surfaces. These colder areas may be inner bin surfaces or the grain itself. Spoilage can occur if this convective air movement is not arrested. Routine aeration of the bin contents will prevent convective air movement.

Maintain a temperature differential of no more 5°C between the grain mass and the average outside air temperature to prevent convective air movement from occurring.

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Basics of Aeration

• Bring the whole grain mass to the same temperature.
• Operate the fan only when relative humidity levels will not add moisture to the grain.
• Operate the fan for enough hours to totally change the whole grain mass temperature, which may require a number of days.
• Become familiar with Equilibrium Moisture Content charts for the grain or beans you are storing (see the section Harvest and Storage in each commodity chapter). Run the fan only under outside conditions that will not add moisture to the stored product. Relative humidity levels of night-time air can add moisture to small grains, beans and natural air dried corn.
• See Table 10-1. Time Required for Aeration Front to Move Through Grain for the aeration time required to completely change the bin content temperature.

CFM = cubic feet per minute; 1 CFM/bu = 13 L/sec/m³

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Grain Storage Monitoring

If you have grain stored on your farm, monitor the bins on a routine schedule.

Bins storing the grain being used regularly for feed can be monitored as theyíre being used. Remember to check the bins that are not having grain removed on a routine basis. Grain can go out of condition quickly. By carefully and diligently monitoring storage bins, growers will be able to detect the warning signs of possible spoilage problems and be able to take appropriate action to prevent further reductions in quality.

Monthly Bin Monitoring Checklist

• Turn on your aeration fan.
• Climb up and look inside the bin. Look for signs of moisture on the underside of the roof. If water droplets or ice are present, aerate the bin. Moisture from the grain has been carried into the attic space and condensed on the roof metal.
• Run the aeration fan if a light dusting of snow has been driven into the top of a storage bin. It will sublimate and be discharged as harmless water vapour. If much greater amounts of snow are found, shovel it out.
• Check for any off-odours. The air should smell like clean grain.
• Check the grain surface to see if it looks the same as the last time. If it looks dull or off-colour, investigate further.
• Check for changes in the static pressure or the working pressure of the fan in the plenum under the aeration floor since last month. A decrease is no cause for concern. An increase, however, indicates that something has increased the resistance of the air as it moves through the grain mass. Investigate deeper into the grain mass.
• Look for any signs of insect activity.
• Record your notes in a monitoring logbook for comparison with the next months' readings.

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Updates on Stored Grain Management: Storing Grain In Bins

No updates available at this time.

Related Links...

• Stored Grain Management
• Field Crop Protection Guide - Publication 812
  • Chapter 8 - Stored Grain

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