Olive Oil facts
Which oil for the salad and which for the pan? How long does a bottle really keep, and why does light ruin it? The basics of buying, storing and using olive oil are simpler than the label makes them look — here is the plain version.
Olive oil is one of the friendliest things in the kitchen and one of the most over-mystified on the shelf. A handful of plain facts cover most of what a cook needs: what the grade words mean, how to keep the oil alive, and which bottle to reach for over the salad versus over the heat. Get those right and you will waste less oil and enjoy more of it.
Which grade, and when
Keep your best extra virgin for raw use — drizzled over vegetables, soup, bread or salad — where its flavour and aromas actually reach you. For everyday frying and high-heat cooking, a plainer ‘olive oil’ (mostly refined, milder, cheaper, with a higher smoke point) does the job without wasting the good stuff, whose delicate character heat would destroy anyway. Many cooks sensibly keep two bottles: a fine finishing oil and a workaday cooking one.
How to store it
Olive oil has three enemies: air, light and heat. Each speeds the oxidation that turns fresh oil stale and eventually rancid. So keep it in a cool, dark cupboard — never on a sunny sill or beside the stove — in a dark glass or tin container, tightly closed between uses. The clear bottle on the hot windowsill is the single most common way a good oil is quietly ruined at home.
How long it lasts
Unlike wine, olive oil does not improve with age — it is a fresh juice, best drunk young. As a rule of thumb it is at its best within around eighteen months of milling, and better still in the first year. That is why a harvest date tells you far more than a distant ‘best before’. Once opened, use a bottle within a couple of months while its aroma is alive. Trust your senses too: fresh oil smells grassy and green, while tired oil smells flat, waxy or crayon-like — that is rancidity, and it is time to let it go.
| Job | Reach for | Why |
|---|---|---|
| Salad, drizzle, dip | Extra virgin | Flavour and aroma matter here |
| Finishing a cooked dish | Extra virgin | Added off the heat, tastes best |
| Frying, roasting, high heat | Plain ‘olive oil’ | Milder, cheaper, higher smoke point |
| Baking (neutral) | Plain ‘olive oil’ | Flavour less critical |
The takeaways
- Save extra virgin for raw use; use a plainer oil for high heat.
- Store cool, dark and closed — air, light and heat are the enemies.
- Buy on harvest date; olive oil is best young, not aged.
- Trust your nose: grassy is fresh, waxy is rancid.
Using olive oil: common questions
Can you cook with extra virgin olive oil?
Yes, and it is safe to do so, but heat degrades its delicate flavour and aromas — so save the best extra virgin for raw or finishing use and cook with a plainer oil.
How long does olive oil last?
It is best within about eighteen months of milling, and better in the first year. It does not improve with age, so buy on the harvest date and use opened bottles within a couple of months.
How should I store olive oil?
Cool, dark and tightly closed, in dark glass or tin, away from sunlight and the stove. Air, light and heat are what turn it stale and rancid.
Does olive oil go bad?
Yes — it goes rancid rather than mouldy. Rancid oil smells flat, waxy or crayon-like instead of fresh and grassy; if it does, discard it.
What is the difference between extra virgin and plain olive oil?
Extra virgin is the top grade, mechanically pressed and full of flavour; plain ‘olive oil’ is mostly refined, milder and cheaper, better suited to high-heat cooking.
Two habits will do more for your cooking than any fancy bottle. First, keep two oils — a good extra virgin you only ever use raw, and a cheaper plain oil for the pan — so you never waste the fine stuff on heat that destroys it. Second, get the good bottle off the counter and into a dark cupboard, and buy on the harvest date, not a vague best-before. Olive oil is a fresh juice, not a keepsake. Treat it like one and it will taste twice as good.
Practical guidance on olive-oil grades, storage and shelf life.