Grain Storage in High Temperatures

As harvest progresses under increasingly warm conditions, effective grain storage is critical to preserving quality and minimising losses. With temperatures climbing, growers are reminded of the importance of timely cooling and moisture management to protect grain from pests, spoilage, and quality degradation.

Cooling Targets: Timing is Key

Grain should be cooled to below 15°C within two weeks of harvest to reduce insect activity and prevent breeding. This is especially important for cereals, where insect pests such as saw-toothed grain beetles and grain weevils can complete their life cycles rapidly in warm conditions.

Recommended cooling milestones:

• Within 2 weeks of harvest: Cool to below 15°C to reduce insect activity.
• Within 3–4 months: Cool to below 12°C to stop insect breeding.
• By end of December: Cool to below 5°C to help kill adult insects and prevent mite populations from increasing.

These targets are based on research showing that most insects stop feeding below 5°C, while mycotoxin formation is more likely between 15–25°C.

Moisture Management: Avoiding Spoilage

Maintaining appropriate moisture levels is equally important for safe storage:

• Cereals: Grain above 18% moisture should be dried immediately. For long-term storage, aim for below 14.5% to reduce food safety risks and mycotoxin development.
• Oilseed Rape (OSR): The lowest acceptable moisture content is 6%, with an ideal range of 7.5–8% for prolonged storage.

Failure to meet these targets can lead to spoilage, reduced marketability, and increased risk of contamination.

Further information can be found on the AHDB website, here.