olive oil does not go off like milk: it does not become dangerous overnight. it does age, though, and old oil loses its aroma, flavour and antioxidants until it turns rancid. here is how to read the date, how long it really lasts and how to tell when it has gone.
expiry date or "best before"?
Olive oil labels in the European Union do not carry a real expiry date but a "best before" date. The difference is set by EU food labelling law:
- "use by" is for perishable foods such as fresh meat or milk, which can become unsafe after that date;
- "best before" tells you until when the product, stored properly, keeps its quality. After it, the food is not unsafe, but it may be less good.
Oil falls into the second group: it contains almost no water, so microbes cannot grow in it. The producer sets the date, usually about 18 months from bottling.
how long does olive oil last?
Almost everything depends on storage. Oil has three enemies: light, heat and air. All three speed up oxidation, which uses up the polyphenols and eventually turns the oil rancid.
- sealed, dark and cool: it keeps well until the date on the label;
- once opened: best used within two or three months, with the cap always closed;
- next to the hob or in the sun: it can spoil within weeks, whatever the label says.
That is why the container matters so much. Clear glass lets light through, dark glass filters some of it, and a tin blocks it completely.
"the date on the label says how long the oil can stay good. whether it does depends on where you keep it."
how to tell if olive oil is rancid
Your nose is enough. Pour a little into a glass, warm it in your hand for a few seconds and smell.
- good oil smells of olives, cut grass, artichoke or almond, and may taste bitter and peppery;
- rancid oil smells of stale nuts, putty, crayons or old butter. It tastes flat and greasy.
Rancidity is a defect: a rancid oil is no longer extra virgin, whatever the label says. To learn more about what the category guarantees, read what extra virgin olive oil really means.
can you use expired olive oil?
If the date passed recently and the oil was stored well, taste it: if it still smells of olives and has no defects, you can use it, perhaps for cooking rather than raw. If it is rancid, keep it out of the kitchen: a little will not poison you, but the oxidation products are not good for you, the antioxidants are gone and it spoils the taste of any dish.
cloudy oil and sediment
Unfiltered oil can be slightly cloudy and leave a sediment: tiny particles of olive, not a defect. Over time, though, that sediment can ferment and give off-flavours, so if you keep oil for a long time, pour off the clear part. And if your oil turns cloudy or thick in winter, it is only the cold: below 8–10 °C some of its components solidify. At room temperature it clears again, unharmed.
frequently asked questions
does olive oil expire?
It has a best-before date rather than a true expiry date, usually about 18 months from bottling. After that it does not become unsafe, but it can lose aroma and flavour and turn rancid.
can you use olive oil after the best-before date?
If the date passed recently and the oil was stored in a dark, cool place, taste it: if it still smells of olives and has no defects you can use it. If it is rancid, do not cook with it.
how long does olive oil last once opened?
Ideally use it within two or three months, keeping it tightly closed, in the dark and away from heat.
how can you tell if olive oil is rancid?
By smell: rancid oil smells of stale nuts, putty, crayons or old butter and tastes flat. Good oil smells of olives, grass or artichoke.