The yellow sticker is only half the trade — the other half happens at your freezer, at ten past nine, deciding what survives the week. Anyone can buy a £3.50 chicken marked down to 90p. The difference between the people who save £30 a month on markdowns and the people who quietly bin half of what they grab comes down to two skills nobody teaches: reading date labels correctly, and knowing what freezes.

The two dates are not the same thing

British food labels carry two different dates doing two different jobs, and conflating them wastes real money:

  • Use-by is the safety date. It appears on perishable food — meat, fish, dairy desserts, prepared salads — and after midnight on that date, the official advice is don't eat it, regardless of how it looks or smells. This is the date yellow stickers orbit: food gets marked down because the shop can't sell it after today.
  • Best-before is a quality date. Food past its best-before is legal to sell, legal to eat, and usually fine — a biscuit goes slightly softer, not dangerous. Whole shelves of the discount retail world (Company Shop, Approved Food, the surplus stores) run on exactly this distinction.

So a use-by markdown is a deadline; a best-before markdown is barely a constraint at all. The single most useful fact in this whole subject: you can freeze food right up to and including its use-by date, and the freezer stops the clock. A chicken frozen at 9pm on its use-by date is, from a safety standpoint, paused indefinitely — the standard advice is to eat it within three to six months for quality, not safety.

One wrinkle worth knowing: some chains have moved milk from use-by to best-before labels specifically to cut waste — Morrisons did it back in 2022 — which makes the sniff test officially sanctioned on those bottles.

What freezes brilliantly

Most of what gets yellow-stickered freezes better than people assume:

  • Bread and bakery — the classic. Sliced loaves toast straight from frozen; a 20p sourdough is a 20p sourdough.
  • Raw meat and fish — freeze in portions on day of purchase, not the whole tray as one brick you'll never defrost sensibly.
  • Milk freezes fine (it goes faintly yellow when frozen; it comes back). Butter and hard cheese freeze well — grate cheese first and it's usable from frozen.
  • Most cooked dishes — that marked-down lasagne or curry freezes as a ready meal you priced at £1.20.
  • Eggs, surprisingly, freeze cracked and beaten, though few people bother.
  • Vegetables mostly want blanching first; or skip the ceremony and cook the marked-down veg into a soup or sauce, then freeze that.

And the short refusal list: salad leaves, cucumber, whole tomatoes, cream, and most yoghurts come out of a freezer as something you don't want. If the sticker is on a bag of watercress, it's tonight's dinner or it's nothing.

Defrosting without poisoning yourself

The rules on the way back out are stricter than on the way in, and they're short:

  • Defrost in the fridge, not on the counter — overnight for most things, a day or more for anything big.
  • Cook within 24 hours of fully defrosting, and treat the original use-by as spent.
  • Never refreeze raw food that's been thawed — but you can cook the thawed meat and freeze the resulting dish. The chilli made from defrosted markdown mince goes back in the freezer with a clean conscience.
  • Rice gets one reheat, ever. Cooked rice left warm is the food-poisoning cliché for a reason.

None of this is exotic — it's the Food Standards Agency's standard guidance, and Love Food Hate Waste covers the details for specific foods if you're unsure about something odd.

Shop with the freezer's diary, not your appetite

The failure mode of markdown shopping is buying like the food is free. It isn't — it's 70% off, which still means 30p of your pound is riding on you actually eating it. Before the haul goes in the basket, the honest questions:

  • Is there freezer space tonight, or are you buying food a shelf can't hold?
  • Will you portion it before freezing, or freeze one unusable slab?
  • Do the fresh-only items — the salads, the cream cakes — fit into the next 24 hours of actual meals?

A workable system: keep one freezer drawer as the markdown drawer, label everything with a marker (contents and the date it went in — frost makes everything anonymous within a fortnight), and run it first-in, first-out. People who do this reliably knock £20–£40 a month off their food spend, because the drawer becomes a rotating stock of proteins and bread bought at 60–90% off.

Too Good To Go bags and Olio pickups obey the same maths, incidentally — the surprise bag is only cheap if it gets eaten.

The supermarkets have already done their part of the deal by pricing Tuesday's chicken at 90p. The freezer is where you do yours.