Keep grain safe in store and water fit for stock.
Moisture, temperature and water readings for harvest, storage and livestock. Tap a problem to jump to it.
Grain too wet to store
Why it happens
Grain exchanges moisture with the air around it. Wet grain lets moulds grow, mites breed and mycotoxins form.
How to tell it apart
A musty smell, crusting on the surface or warm patches mean the problem has started. Grain can look fine and still be too wet, so measure.
How to test
- Take samples from several points and depths, at the same places each time.
- Measure each sample with a calibrated grain moisture meter, set to the right crop.
- Record the readings and the grain temperature.
Grain meters such as the MC7825G, MT40 PRO or LDS-1G cover different crops and sample sizes.
Good and bad readings
| Cereal moisture content | What it means |
|---|---|
| Below 13% | Moisture uptake is limited, effectively preventing mites breeding |
| Above 14.5% | Food safety risk increases |
| 18% or above | Dry immediately |
Source: AHDB, Grain storage moisture targets for cereals and oilseed rape. For oilseed rape AHDB gives 7.5–8% for prolonged storage.
What next
Dry wet batches first, starting with anything at 18% or more. AHDB says that if moisture rises by 2% or more in one area in a week, find the cause (condensation, leaks, hot spots or insects) and act.
Common mistakes
One sample from the top of the heap; an uncalibrated meter; wrong crop setting.
Hot spots in store
Why it happens
Grain is a good insulator, so heat from insects, mould or warm harvest grain builds up in pockets.
How to tell it apart
A steady rise in one spot while the rest of the store stays cool points to activity in that pocket, not the weather.
How to test
- Record grain temperature at fixed points and depths.
- Check at least monthly in winter and more often after harvest.
- Compare each reading with the last one at the same point.
Good and bad readings
AHDB recommends storing cereals below 14.5% moisture and 5°C (malting barley not below 10°C). At 5°C, wheat at 14.5% moisture has an equilibrium relative humidity of 56%; at 25°C it is 66%. Mould growth and mite reproduction stop below 65%. Sources: AHDB moisture targets and AHDB hazards during longer-term storage.
What next
Cool the grain with aeration and check the hot spot for insects or wet grain.
Common mistakes
Measuring only at the surface; not recording readings at the same points.
Airflow through the store
Why it happens
Aeration cools grain only if air actually moves through it. Blocked ducts or uneven filling leave pockets that don't cool.
How to tell it apart
Areas that stay warm while the fans run suggest poor airflow there.
How to test
- Measure air speed at duct outlets or the grain surface with the fans running.
- Compare readings across the store.
- Look for spots with much lower airflow.
A vane anemometer such as the BT-846A measures air speed.
What next
Clear blocked ducts and level the grain surface. We could not find a sourced air-speed figure to quote here; for fan sizing ask AHDB or your store equipment supplier.
Common mistakes
Measuring in only one spot; measuring with fans off.
Water for livestock
Why it happens
Troughs and private supplies can change with weather, run-off and algae.
How to tell it apart
A sudden change in readings from your usual baseline tells you more than one reading on its own.
How to test
- Record a baseline for pH, conductivity (EC) and TDS from your usual supply.
- Re-test troughs regularly and after heavy rain.
- Compare with the baseline.
A multi-parameter monitor such as the PH-W3988 can log these readings.
What next
We have not found a UK source with livestock drinking-water limits to quote here. If readings change, ask your vet or water supplier. Private drinking water supplies are regulated by your local council.
Common mistakes
No baseline; uncalibrated probes.
Instrument for this step
PH-W3988 6-in-1 WiFi Water Quality Monitor - pH & TDS Water Quality Tester WiFi£78.99
FAQs
Which grain meter should I choose?
It depends on the crops and how you sample. Check the crop list and sample method on each product page.
How often should I check grain in store?
AHDB advises monitoring at the same locations each time and recording at least monthly in winter.
Can I get a VAT invoice?
Yes. All prices include VAT and VAT invoices are available.
Need help choosing?
Contact us and tell us what you need to measure.