What do the stars on a freezer actually mean?

The star markings are a European standard that predates almost every other label on the appliance, and they still appear on the ice box of a fridge, on a freezer compartment door and on frozen food packaging. Matching the stars on the packet to the stars on your appliance tells you how long that item will keep. It is a genuinely useful system that almost nobody has been taught to read.

Safety

Step by step

1. Find the star marking on your appliance.Usually moulded or printed on the freezer compartment door, on the flap of an ice box, or on the rating plate inside the fridge. Check it — the small ice box inside an older fridge is often only one or two star.
2. Read one star as -6°C and about one week.The small ice box in a basic fridge. It will keep bought frozen food edible for a few days to a week and it will make ice cubes. It will not freeze anything from fresh and it will not hold ice cream properly.
3. Read two stars as -12°C and about one month.A slightly better ice box or a small compartment. Still storage only. Frozen food packaging usually gives the two star keeping time as roughly one month.
4. Read three stars as -18°C and long-term storage.This is a proper freezer temperature. Bought frozen food keeps until its own best-before date. But a three star compartment still cannot freeze fresh food — it holds -18°C, it does not have the capacity to pull warm food down fast.
5. Read four stars as -18°C or below, plus a freezing capability.The fourth star is the important one. It means the appliance can freeze a stated quantity of fresh food within 24 hours, usually written on the rating plate in kilograms per 24 hours. This is the only rating that lets you freeze your own cooking, meat or bread.
6. Match the stars on the food packet to the stars on your compartment.Most frozen food packaging carries a small table: one star, one week; two stars, one month; three or four stars, until the date shown. That is exactly what the stars are for.
7. Do not put fresh food into a low-star compartment to freeze it.It freezes slowly, forms large ice crystals that wreck the texture, and spends hours passing through temperatures where bacteria are still active. It also warms everything already in there.
8. Use the fast freeze function on a four star freezer when you add a lot at once.It runs the compressor continuously to pull the cabinet colder before the warm food goes in, which protects everything already frozen and gets the new food through the freezing range quickly.

Tips

• The stars describe temperature capability, not current temperature. A four star freezer left with its door ajar is not at -18°C, whatever the stars say. Check with a thermometer.
• The freezing capacity in kg per 24 hours is worth knowing before a big batch cook. Exceeding it means everything freezes slowly, including the food that was already in there.
• An appliance sold with a blue-shaded three star symbol plus a separate star is the older way of writing four star. Modern labelling usually just shows four stars.

Common mistakes

• Treating a three star compartment as a freezer for home cooking — It will hold food that is already frozen but it cannot freeze it quickly. Batch-cooked meals put into a three star compartment freeze slowly, taste worse and spend longer in the range where bacteria grow.
• Assuming the ice box in an old fridge is a freezer — Most are one or two star. Anything stored there for more than a week or two is degrading, and frozen food bought for the month will not survive it.

Questions people ask