AdBlue® doesn't last forever. It has a shelf life, and that shelf life depends almost entirely on one thing: the temperature it is stored at. Kept cool, it will stay within specification for years. Left in a hot shed or in full sun, it can drift off-spec within months. Knowing how the numbers work helps you decide how much to buy at once and where to keep it.
Shelf life by storage temperature
The ISO 22241-3 standard gives guidance on how long AdBlue can be expected to stay within specification when stored at a constant temperature. The figures below assume sealed containers of product that was in spec to begin with.
| Constant storage temperature | Expected shelf life |
|---|---|
| At or below 10°C | About 36 months |
| At or below 25°C | About 18 months |
| At or below 30°C | About 12 months |
| At or below 35°C | About 6 months |
| Above 35°C | Test before use |
The pattern is clear. Each step up in temperature cuts the expected life sharply. Moving from 25°C storage to 35°C storage takes you from around 18 months to around 6.
Why heat shortens shelf life
Urea dissolved in water slowly breaks down into ammonia and carbon dioxide. At cool temperatures this happens very slowly; as the temperature climbs, it speeds up. Over time the urea content can fall below the specified range of 31.8–33.2%, and by-products such as biuret build up. ISO 22241-1 limits biuret to 0.3%, because it can form deposits in the SCR system.
A strong ammonia smell when you open a container is the most obvious warning sign. A faint smell around AdBlue is normal. A sharp, eye-watering one suggests the product has been kept hot for too long.
What constant temperature means in real storage
The table assumes steady temperatures, but real storage isn't steady. A container in a shed might sit at 18°C overnight and 40°C in the afternoon. What matters is the total heat it sees over time. A few hot days won't ruin good product, but a whole summer of hot afternoons adds up.
For Australian sites, some practical takeaways:
- Stock kept in a ventilated, shaded building in the southern states may sit in the 18–25°C band for much of the year.
- Stock kept in a metal shed, a shipping container or in the open in northern and inland areas can spend long periods above 30°C.
- Buy in quantities you will use well within the shelf life for your conditions. A bigger pack isn't better value if part of it goes off-spec before you reach it. Pack sizes from 10 L drums to bulk are on the price list.
- Rotate first in, first out, and mark delivery dates on every container.
Shelf life applies to what is in the vehicle too. AdBlue in a truck that runs every day is used within weeks, so it is rarely a concern. A machine parked up for months over summer, such as a harvester between seasons or plant on a standby site, may be carrying old product. Before putting it back to work, check how long the AdBlue has been in the tank and, if in doubt, drain it and refill with fresh product.
Checking stock you're unsure about
If you find an old IBC or a pallet of drums with no date on it, don't guess. A refractometer will tell you whether the urea concentration is still in range, which is a useful first check. It won't tell you anything about biuret, metals or other contaminants. For that you need a lab test against ISO 22241-1.
Signs that stock shouldn't be used without testing:
- A strong ammonia odour.
- Cloudiness, discolouration or visible particles.
- White crystals inside the container or around the cap, a sign of evaporation and possible change in concentration.
- Unknown age, or known storage above 35°C for long periods.
One thing to do today: put an inexpensive min/max thermometer where your AdBlue is stored and read it after a week. It tells you which row of the table you are really in, which is far more useful than guessing. If the maximum regularly goes past 30°C, find a cooler spot or add shade, and consider ordering smaller quantities more often.
How Liquidia can help
Every batch of Liquidia AdBlue is lab-tested, backed by a 12-month product guarantee, and a Certificate of Analysis is available on request. See our VDA and ISO certification, or download documents from the resources page.