Does Olive Oil Go Bad? How Long It Lasts and How to Store It
Yes, olive oil goes bad, but slowly. Here is how long it lasts unopened and opened, how to tell if it has turned rancid, and how to store it.
Quick answer: Yes, olive oil goes bad, but slowly. It does not spoil like milk: it oxidises and turns rancid. An unopened tin or bottle of good extra virgin olive oil usually keeps its best quality for about 12 to 24 months, and once opened we suggest using it within about three months. Keep it cool, dark and tightly closed, and trust your nose: a waxy, crayon-like or stale-nut smell means it has turned.
Does olive oil go bad? It is one of the questions we hear most, usually about a bottle that has sat at the back of the cupboard for longer than anyone remembers. This guide gives you the numbers, the smell test, a simple storage routine and a way to read the dates on a label.
Key takeaways
- Olive oil does go bad. With enough time all olive oils, even the best, become rancid through oxidation, according to the UC Davis Olive Center.
- Unopened extra virgin olive oil typically keeps its best quality for about 12 to 24 months. Once opened, use it within about three months.
- Oxygen, light, heat and time are what age the oil. A cool, dark cupboard and a tightly closed cap do most of the work.
- You can tell by smell and taste. Fresh oil smells grassy or fruity and tastes bitter and peppery. Rancid oil smells of wax, crayons or old nuts.
Does olive oil go bad?
Yes. Olive oil is a fat, and fats react with oxygen. Over months the oil slowly oxidises, the fresh, green aromas fade, and eventually a flat, waxy smell takes over. That is what rancid means.
It is a different process from spoilage in dairy or meat. What changes is quality: flavour, aroma and the freshness that makes extra virgin olive oil worth buying. The UC Davis Olive Center is clear in its list of olive oil myths: olive oil does not get better with age, and with enough time every olive oil becomes rancid.
How long does olive oil last?
There is no single number, because it depends on the oil, the packaging and how you store it. As a rule of thumb:
- Unopened: about 12 to 24 months. A 2018 peer-reviewed study notes that the shelf life of extra virgin olive oil has been assessed at 12 to 18 months, and that well-sealed oil can reach a second year with its sensory properties unchanged.
- Opened: aim to finish it within about three months. The UC Davis Olive Center advises buying a size you can use within weeks or a few months of opening.
The clock starts at harvest and bottling, not when you open the cap, which is why the dates on the label matter.
What makes olive oil go bad?
Four things age olive oil, and you can influence three of them:
- Oxygen. Every time you open the bottle, air gets in. A half-empty bottle has more oxygen to react with than a full one.
- Light. Light speeds up oxidation, which is why good olive oil is sold in tins or dark glass.
- Heat. Warm storage ages oil faster. In a 2018 study in the journal Heliyon, extra virgin olive oil kept at 26°C showed a significant rancid flavour after 125 days in a tin, while oil kept at 6°C in glass showed no defects.
- Time. Even in perfect conditions, oil slowly loses its freshness.
The natural antioxidants in the oil, such as polyphenols, slow this process down, but they cannot stop it.
How to tell if olive oil has gone bad
Pour a little into a small glass, cover it with your hand and warm it for a minute. Then smell it and taste a small sip.
- Smell: fresh extra virgin olive oil smells of cut grass, green fruit, tomato leaf or artichoke. Rancid oil smells waxy, like crayons, putty, old nuts or stale cooking fat.
- Taste: fresh oil is fruity with some bitterness and a peppery kick in the throat. Rancid oil tastes flat, greasy, sour or stale, and the pepper is gone.
- Look: colour is not a reliable guide, and cloudiness or sediment does not mean the oil is bad, as the UC Davis Olive Center notes. Smell and taste are what count.
Rancidity is first of all a quality problem: the oil tastes bad and has lost what makes it worth using. We would not cook with it or serve it, and if you are unsure, throw it away.
How to store olive oil
- Keep it cool. A cupboard away from the oven, hob and sunny windows is ideal. The UC Davis Olive Center cites research showing that extra virgin olive oil keeps longer at 15°C than at 25°C.
- Keep it dark. Use a tin, a dark glass bottle or a cupboard. Clear bottles on an open shelf are the worst case.
- Close the cap every time. Less air means slower oxidation.
- Buy a size you will finish. A 1 litre tin used within a few months is fresher than a 5 litre tin that takes a year. If you buy big, decant into a smaller bottle and keep the rest sealed.
- Do not decant into a cruet and leave it on the hob.
What the dates on the label tell you
A best before date is a quality guide, not a safety cut-off. It tells you how long the producer expects the oil to be at its best when stored properly. The harvest date tells you far more: the more recent the harvest, the fresher the oil.
Under the EU marketing rules, extra virgin olive oil must have free acidity of 0.8% or less, a peroxide value of 20 mEq O2/kg or less, K232 of 2.50 or less and K268 or K270 of 0.22 or less. Peroxide value is the lab measure of early oxidation. Those limits are set out in Commission Delegated Regulation (EU) 2022/2104. Our guide to olive oil acidity explains the first of those figures, and how to tell if olive oil is real explains what to look for on a label.
How we keep our oils fresh
Freshness starts before the oil reaches your cupboard. Our oils are cold extracted below 27°C, stored under nitrogen and packed in light-proof packaging, and every batch has a LOT number with its harvest date, best before date and lab report.
- Memilon Crete, 100% Koroneiki from Phaistos, 0.29% acidity and 610 mg/kg polyphenols. Our current batch was harvested on 20 November 2025, bottled on 11 September 2026 and carries a best before date of 10 September 2028, with K232 at 1.762 against the legal limit of 2.50.
- Memilon Lesvos, rare Kolovi from Plomari, 0.29% acidity and 512 mg/kg polyphenols. It comes in a tin, harvested 27 November 2025, bottled 7 September 2026, best before 7 September 2028.
- Memilon BIO Crete, certified organic Koroneiki, 0.18% acidity and 810 mg/kg polyphenols. It comes in a glass bottle, so keep that one in a cupboard rather than on the counter.
You can look up the lab results for your batch with the LOT number on the tin, read more on our lab analyses page, and see all three oils, with free shipping on every order, in our Greek olive oil collection.
Does olive oil go bad: frequently asked questions
How do I know if olive oil is bad?
Smell and taste it. Fresh oil is grassy or fruity and slightly bitter and peppery. If it smells of wax, crayons, putty or old nuts, or tastes flat and greasy, it has gone rancid.
Is it safe to use expired olive oil?
A best before date marks quality, not safety. An oil a few months past its date can still smell and taste fine, and then it is fine to use. If it smells or tastes rancid, do not use it: it will spoil the dish, and it is not worth keeping.
Does unopened olive oil go bad?
Yes, more slowly. Unopened oil still ages with time, light and warmth, so it also has a limit, usually around 12 to 24 months. A tin or dark bottle stored somewhere cool and dark lasts longest.
Does olive oil go bad in the fridge?
No. The fridge slows ageing, but the oil turns cloudy and thickens when cold. That is harmless and goes away at room temperature. The UC Davis Olive Center notes that oil kept in a freezer at -20°C held its quality better than oil at fridge temperature (4°C), though for everyday use a cool, dark cupboard is simpler.
Can I reuse olive oil after frying?
You can strain it and keep it cool and dark, but it ages with every use. Throw it away if it is dark, foamy, thick or smells off. Our guide to the olive oil smoke point covers cooking with extra virgin olive oil in more detail.
Sources
- UC Davis Olive Center, "Ten Myths and Facts About Olive Oil" (2019): ageing, storage temperature, cloudy oil.
- Sanmartin C. et al., "The effects of packaging and storage temperature on the shelf-life of extra virgin olive oil", Heliyon 4(11) (2018).
- European Commission, Delegated Regulation (EU) 2022/2104: quality characteristics of olive oil categories.
This article is general information about olive oil and does not replace advice from a doctor or dietitian.
