How Long Does Yoghurt Last? (Opened, Unopened & Greek vs Regular)
Yoghurt is the dairy product people are most likely to keep past its best-before date and still eat — sometimes sensibly, sometimes not. The line between “still perfectly fine” and “time to bin it” depends on whether the seal is broken, how it’s been stored, and what that pooled liquid on top actually is. Here’s what the food-safety guidance actually says.
The best-before date on a yoghurt tub is a quality marker, not a safety deadline. Yoghurt’s acidity and live bacterial cultures create an environment hostile to most harmful pathogens, which is why FoodSafety.gov puts yoghurt in the “1–2 weeks opened” bracket rather than the tighter window you’d apply to raw meat or soft cheese. But “still safe” has its limits, and those limits tighten dramatically once you break the seal.
The Numbers by State
| Condition | How long it lasts |
|---|---|
| Unopened, fridge (≤4°C / 40°F) | 1–3 weeks past best-before date |
| Opened, fridge | 5–7 days from opening |
| Greek yoghurt, unopened | 1–3 weeks past best-before date |
| Greek yoghurt, opened | 5–7 days from opening |
| Left at room temperature | Discard after 2 hours (per FDA guidance) |
| Frozen | 1–2 months (texture degrades) |
These figures are consistent with FDA safe food storage guidelines and the USDA’s cold storage charts. The 5–7 day opened window is the conservative benchmark for cultured dairy; in practice, a tub stored correctly and opened only with a clean spoon often holds for a day or two longer, but that’s the buffer, not the target.
Unopened: How Much Buffer Do You Actually Have?
Yoghurt’s acidity (a pH of roughly 4–4.5) and its live cultures — typically Lactobacillus bulgaricus and Streptococcus thermophilus — compete aggressively with spoilage organisms. This is why an unopened tub sitting at a steady 4°C can hold quality well past its stamped date.
The buffer depends on two things: fridge temperature and whether the tub has ever been warmed. A tub that spent two hours on a supermarket loading dock in summer has already used up part of its buffer before you bought it. A tub that went straight from a refrigerated shelf to your fridge bag to your fridge still has the full buffer intact. When in doubt, use smell and texture — not arithmetic from the printed date — as your guide.
Opened: The 5–7 Day Rule and Why It Matters
Breaking the seal changes everything. Every time you open the tub, air comes in. Every spoon — even a clean one — introduces trace microbes. The culture environment that kept the yoghurt stable is now being diluted and disrupted by outside organisms, and the clock starts running from that first opening, not from the printed date.
The most common mistake is using the same spoon twice — back in for a second scoop, or licked and returned to the pot. Saliva contains amylase and a mix of oral bacteria that can spoil a tub within 24 hours. Use a clean spoon every time, replace the lid firmly after each serving, and keep the tub on a cool interior shelf rather than the door.
For large format tubs (750 g or 1 kg), portion out the week’s worth into a smaller container at the start of the week. The main tub stays sealed longer and the portioned container gets eaten promptly without repeated opening of the full pot.
Greek vs Regular: Same Shelf Life, Different Freeze
Greek yoghurt is made by straining regular yoghurt through a fine mesh to remove most of the liquid whey, leaving a thicker, denser, higher-protein product. That straining process doesn’t meaningfully change how long it keeps in the fridge — unopened and opened Greek yoghurt follows the same timelines as regular.
Where Greek yoghurt wins is in the freezer. Its lower moisture content means fewer ice crystals form during freezing, so the texture change on thawing is slightly less dramatic than with regular yoghurt. It’s still grainy by the standards of fresh yoghurt, but it performs better in smoothies and baked goods than its regular counterpart straight from the freezer.
That Liquid on Top: Whey, Not a Warning Sign
The clear, slightly yellowish liquid that accumulates on top of undisturbed yoghurt — particularly Greek and natural varieties — is whey: the liquid protein fraction that separates as the yoghurt sits. It’s nutritious (high in protein and calcium), completely harmless, and a normal feature of live-culture dairy.
Stir it back in before eating. Pouring it off repeatedly dries out the yoghurt faster and discards a reasonable amount of nutrition along with it. The only liquid that should concern you is whey that has turned pink, orange or brown — that’s a sign of mould rather than normal separation, and the whole tub should go.
Freezing: Useful for Waste, Not for Texture
If you have half a large tub going stale, freezing is a legitimate rescue move — but set your expectations. Yoghurt’s protein-water matrix doesn’t survive freezing without breaking apart. On thawing, it becomes grainy and slightly lumpy: fine for blending into a smoothie or stirring into a curry marinade, noticeably off for eating with granola or serving as a dip.
Freeze in small portions — ice-cube trays work well for smoothie-sized quantities, small airtight containers for larger batches. Leave space for expansion. Use within 1–2 months for best flavour. Thaw in the fridge overnight; never refreeze yoghurt that has already been thawed.
How to Tell When Yoghurt Has Gone Off
The reliable signals, in order of confidence:
- Visible mould. Any fuzzy, pink, green, black or orange growth means the whole tub goes. Don’t scoop around it — soft dairy allows mould to penetrate further than the visible patch.
- A sharply sour or putrid smell. Fresh yoghurt smells clean and mildly tangy. If it smells aggressively sour, fermented or frankly unpleasant, trust that reading and discard it.
- Chunked or curdled texture. Yoghurt that has separated into solid lumps and liquid — beyond the normal light whey separation — has gone. Stir it; if it doesn’t recombine smoothly, it’s done.
- Unusual colour. Standard yoghurt is white to pale cream. Pink, grey or green tints indicate spoilage.
Things that look concerning but aren’t: clear-to-pale-yellow whey pooling on top (harmless, stir it in); a more sour taste than usual without any of the above visual or olfactory signs (natural acidification as the cultures continue working — still safe to eat).
The Practical Rule
Buy the size you’ll actually finish within a week of opening. The unit price on a 1 kg tub looks attractive until half of it goes in the bin at day ten. If your household uses yoghurt sporadically, smaller individual pots — opened only when needed, consumed in one or two sittings — produce far less waste than the economy size. If you do buy large, portion it immediately and freeze anything you won’t reach in five days.
Tracking what you have — and when you opened it — is where most of the yoghurt waste problem lives. It’s the same pattern that kills leftovers, soft cheese, and berries: not a lack of knowledge about shelf life, but a lack of visibility into what’s in the fridge and how long it’s been there. The broader case for fixing that is in how to stop wasting food.
Frequently Asked Questions
How long does unopened yoghurt last in the fridge?
Commercially produced, unopened yoghurt typically keeps 1–3 weeks past the printed best-before date when stored at or below 4°C (40°F). The date on the tub is a quality marker, not a safety cut-off — the live cultures and acidity in yoghurt actively suppress harmful bacteria, giving it meaningful buffer. That said, the buffer shrinks if the fridge runs warm or the tub has been left out at room temperature, so check the smell and texture before eating if you're significantly past the date.
How long does yoghurt last once opened?
Once you've broken the seal, yoghurt should be eaten within 5–7 days regardless of what the best-before date says. Introducing a spoon — even a clean one — brings in trace amounts of bacteria and speeds deterioration. Cover the tub tightly with its lid or clingfilm between uses, and don't double-dip with a used spoon. For large pots you won't finish in a week, spoon out individual servings into a smaller container rather than repeatedly opening the main tub.
Does Greek yoghurt last longer than regular yoghurt?
In practice, no — they keep for about the same amount of time. Greek yoghurt is strained to remove most of the whey, making it thicker and higher in protein, but the straining process doesn't significantly change its fridge life. Both unopened and opened Greek yoghurt follow the same 1–3 weeks / 5–7 days rules as regular yoghurt. Greek yoghurt does freeze better (its lower moisture content means less texture change), but in the fridge the difference is negligible.
Is it safe to eat yoghurt with liquid on top?
Yes. The liquid that pools on top of yoghurt — especially Greek and natural varieties — is simply whey, a protein-rich liquid that separates when the yoghurt sits undisturbed. It's completely safe and nutritious. Stir it back in before eating, or pour it off if you prefer a thicker consistency (some people add it to smoothies or soup). Only discard yoghurt if the liquid is pink, orange or otherwise discoloured — that's a sign of mould, not whey.
Can you freeze yoghurt?
Yes, but with a texture caveat. Freezing causes the water in yoghurt to crystallise, breaking the emulsion — when thawed, it becomes grainy and slightly watery rather than smooth and creamy. Frozen-then-thawed yoghurt works perfectly in smoothies, muffins, pancake batter or as a marinade ingredient, but it's not great for eating straight or as a topping. Freeze in an airtight container, leaving room for expansion, and use within 1–2 months. Thaw overnight in the fridge.
How can you tell if yoghurt has gone off?
The main signs are: a sour smell that goes well beyond the usual mild tang; visible mould (pink, green, black or fuzzy patches — distinct from the harmless clear-to-yellow whey); and a curdled or chunky texture that wasn't there when the pot was first opened. Taste shouldn't be your first check — if something looks or smells wrong, discard it. A brief window of more-sour-than-usual taste without visible mould or off-smell is usually just natural acidification and is safe to eat.
Never forget about a half-open tub at the back of the fridge again.
Pantree tracks what’s in your fridge and pantry, reminds you before things expire, and turns what you have into something to cook tonight. Free on the App Store.
