Why the First Few Hours Matter Most

Power cuts are rarely dramatic. More often than not they arrive quietly — a flicker, a click, and then silence from the fridge. Storm damage, a fault on the local network, or an unplanned outage while you're halfway through the weekly shop. Whatever the cause, the clock starts ticking the moment the compressor stops.

Your fridge sits at around 4°C and your freezer at -18°C. Once the power goes, both begin to drift upwards. The good news is that a well-stocked, well-managed fridge and freezer will hold their temperature for far longer than most people expect — provided you resist the temptation to keep opening the door "just to check".

This guide is about buying yourself time, judging what is still safe, and knowing when to be firm with yourself and throw something away.

Keep the Doors Shut

The single most useful thing you can do is nothing at all. Leave the fridge and freezer doors closed.

• Fridge: a closed fridge will hold a safe temperature for roughly four hours.
• Freezer: a full freezer will keep food safe for around 48 hours; a half-full one for about 24 hours.

Every time you open the door, you lose cold air and replace it with warm room air. If you genuinely need something, decide what it is before you open the door, take it out in one movement, and shut it again immediately.

If you have a chest freezer, resist the urge to lift the lid at all. Cold air sits in the bottom and stays there, so the contents near the surface will hold surprisingly well.

Monitor Your Temperatures

An appliance thermometer is one of the cheapest bits of kit you can own, and it takes the guesswork out of a power cut. Keep one in the fridge and one in the freezer at all times, not just during an outage. If you don't have one, place a fridge thermometer near the front where the temperature fluctuates most.

The numbers that matter:

• Fridge: food should stay at or below 5°C.
• Freezer: food should stay at or below -18°C, though it remains safe to refreeze if it still contains ice crystals or has not risen above 4°C.

Once the power returns, check the thermometer before you check anything else. If the fridge stayed at or below 5°C throughout, your food is fine. If the freezer stayed below -18°C, or the contents are still rock solid, you can refreeze them — though texture may suffer.

Use Cool Bags, Ice Packs and a Little Ingenuity

If the outage is forecast — a storm warning, for instance — you can prepare. Turn the fridge and freezer to their coldest setting a few hours beforehand so they start from a deeper chill. Freeze a few bottles of water or spare ice packs in advance; they're useful for cool bags and for dropping into the fridge itself.

During a cut:

• Pack the most perishable items — milk, cooked meats, soft cheese, leftovers — into a cool bag with ice packs.
• Wrap the freezer in blankets or old duvets, but never cover the back or vents if the appliance is still running.
• Group frozen items tightly together in the centre of the freezer. A tight block of food stays cold far longer than items spread out.
• If a neighbour still has power, ask whether they can take a bag of frozen food. This is what communities are for.

Avoid putting warm food into the fridge or freezer. It raises the temperature for everything around it and undoes the cold you've worked to protect.

What to Keep and What to Bin

Be honest and be strict. The general rule is that perishable food left above 5°C for more than two hours should be thrown away. That includes milk, yoghurt, cooked meat, prepared salads, soft cheeses, and anything containing cream or custard.

Raw meat, poultry and fish that have warmed up should go in the bin, not back in the fridge. Never taste food to test whether it's safe — the bacteria that cause food poisoning don't always announce themselves with a smell or a taste.

Items that survive a power cut comfortably include hard cheeses, butter, jam, most condiments, fresh fruit and vegetables, bread, and unopened jars and tins. These can usually be kept if they feel cool to the touch.

Defrosted food that has stayed cold — below 5°C — can be cooked thoroughly and eaten straight away, but it should not be refrozen. Cook it, eat it, and don't keep the leftovers for long.

Preparing Before the Lights Go Out

A little groundwork means a power cut becomes an inconvenience rather than a food bill. Keep your fridge and freezer reasonably full — a full freezer holds its temperature markedly better than an empty one. Freeze bread, milk and batch-cooked meals so you always have something that will survive a long outage.

If your power does go out, report it to your network operator on 105 — a free, UK-wide number that works for any distribution network. And if you're unsure whether something is safe, remember the old adage: when in doubt, throw it out. A wasted tub of leftovers is far cheaper than a weekend spent unwell.