What do I do if my freezer breaks down or loses power?

The instinct is to open the freezer and check. That is the one thing that makes it worse. A closed freezer is a very effective insulated box, and every opening costs hours.

Safety

Step by step

1. Keep the door shut.The single most important action. A full chest or upright freezer holds food safely for around 24 hours unopened, and a half-full one about 12. Opening it repeatedly can halve that.
2. Fill the empty space.If it is half empty, pack the gaps with newspaper, towels or bags of ice. Thermal mass is what keeps it cold, and air is what does not.
3. Move things together.If you must open it, group the contents into one tight block. Items packed against each other keep each other frozen far longer than items spread out.
4. Get ice or dry ice if the outage is long.Bags of ice on top of the food. Dry ice is more effective still if you can get it — handle it only with gloves and never in a sealed space.
5. Use a fridge thermometer inside.It removes the guesswork. A permanent freezer thermometer is inexpensive and tells you immediately whether the contents stayed below -18°C.
6. Judge each item by ice crystals when power returns.Still containing ice crystals and cold to the touch means it can stay frozen or be refrozen. Fully thawed but still fridge-cold means cook it now or discard it.
7. Discard anything that has warmed and softened.Above 8°C for more than two hours means bin it. This applies particularly to raw meat, fish, shellfish, cooked dishes, dairy and ice cream.
8. Cook the borderline items immediately.Anything thawed but still cold can be cooked thoroughly and eaten or refrozen as a cooked dish. Do it the same day.
9. Do not taste to check.Food can carry a dangerous bacterial load with no change in smell, appearance or taste. Judge by temperature history only.
10. Check your insurance.Many UK home contents policies cover freezer contents spoiled by a breakdown or a power cut, usually up to a few hundred pounds. Photograph what you discard before binning it.

Tips

• Keep it shut. Every opening costs hours of safe time.
• A frozen coin on a frozen cup of water is the classic outage indicator — if the coin has sunk, it thawed while you were away.
• Photograph discarded food before binning it; contents insurance often covers it.

Common mistakes

• Opening the freezer to see how things are — Cold air falls out and warm air replaces it, and the contents lose several hours of safe holding time each time. A closed freezer is doing its job; checking it is what defeats it.
• Deciding by smell whether thawed food is safe — The bacteria that cause food poisoning frequently produce no smell, no discolouration and no change in taste. Temperature and time are the only reliable evidence.

If it doesn't work

Questions people ask