Grain Cooling Update

Tom Burns

Early last month we sent a newsletter – “Adesco Aeration Guide 2021” to all our grain customers to advise on managing the newly harvested/treated grain in store. Click here to download it.

Ambient temperatures over the last few weeks have fluctuated widely. Daytime highs of 20°C combined with a few nights where temperatures were as low as 8°C. Overall mean daily temperatures were 2°C higher than the average of the past 4 years which makes the cooling of grain more challenging. It is critical to cool grain to prevent insect growth.

In recent weeks, we have visited many stores, taking samples and checking temperatures. Grain temperatures ranged between 15-19°C and a few “hotspots” were also found.

Target temperatures are shown below, it is important that people take advantage of low nighttime temperatures to cool the grain.

Target Stored Grain Temperatures 

  • Grain temperature should not exceed 25°C
  • Grain temperature below 15°C within 14 days of harvest
  • Grain temperature below 10°C within 28 days of harvest

Remember that cooling is only effective when the ambient air temperature is at least 4°C lower than the grain temperature. This is the golden rule of cooling.

Given the length of time since the last of the grain was harvested, it is essential that it is aerated immediately (if not done so already) in order to bring it down to the target temperatures above. Where we have discovered hotspots, store operators have been informed and the following actions were advised:

  • Increase air supply to the affected area
  • Use spear fans to increase aeration
  • Investigate if aeration ducts/pipes have been blocked (if that is possible)
  • Take out the grain from the store (least desirable)
  • Check and record the grain temperature daily – once cooled below 10°C, the frequency of checking can be reduced to fortnightly

To prevent condensation the air above the grain must be kept at the same as the ambient temperature, so ventilation/extraction is essential.