Olive oil offerings

The supermarket shelf is a wall of green bottles making the same promises, and none of them tells you the one thing that matters: whether you’ll like the oil inside. Here is how to cut through it — taste over colour, freshness over hype, and the four enemies you must keep at bay.

Choosing olive oil looks harder than it is, because the shelf is designed to confuse you: dozens of bottles, all green, all promising extra-virgin purity and Mediterranean sunshine. The honest truth is that quality and price only loosely track each other, and the single reliable test is the one the packaging cannot give you — putting the oil in your mouth. Once you accept that, the whole business gets simpler. Buy, taste, remember what you liked, and learn to keep it well.

Colour tells you nothing

Start by unlearning the most common mistake: you cannot judge an oil by its colour. Green does not mean better and gold does not mean milder — colour reflects the chlorophyll in the fruit, which depends on variety and ripeness, not quality. This is exactly why professional tasters use an opaque blue glass, so the eye cannot bias the tongue. If a bottle is tinted dark or sold in a can, that is often a good sign, because it is protecting the oil from light. Judge by taste, or by a trustworthy label, never by the shade.

The four enemies

Olive oil is a living, perishable food, and four things degrade it: age, heat, air and light. Age because oil is best young and fades over months; heat and light because they speed the chemistry of going rancid; air because oxygen oxidises the oil the moment the bottle is opened. This is why the old advice holds — keep oil in a cool, dark cupboard, away from the stove, tightly closed. It is also why a giant catering tin is a false economy for a small household: you cannot use it fast enough before air undoes it.

Enemy	What it does	Your defence
Age	Flavour fades; oil turns flat, then rancid	Buy recent, check harvest date, use within months of opening
Heat	Speeds rancidity	Store away from the oven and hob
Air	Oxidises the oil once opened	Keep the cap tight; buy a size you’ll finish
Light	Accelerates spoilage	Dark glass, a tin, or a closed cupboard

The darkness rule — with an asterisk

Here is a bit of nuance the rules-of-thumb miss. The advice to hide oil from light is sound, but it matters most for oil that will sit around for a long time. Some producers who sell in clear bottles argue — not unreasonably — that most households finish their oil long before light does real harm. Both things are true: light degrades oil, and speed of use is your best protection. The practical lesson is the same either way. Buy a size you will actually get through, keep it closed and cool, and do not treat a good oil as a trophy to be admired for a year.

Buy where you can taste

The best place to buy oil is somewhere that lets you taste and compare — a specialist shop, a market stall, a mill — and whose staff can actually tell you something about what you are drinking. Some of the finest oils come from Greece and Spain as well as Italy, often at honest prices, but the label alone will not tell you if it suits your palate. When you find an oil and a style of olive you like, write it down. The best oil in the world is simply the one you enjoy and will use.

• Ignore colour — it predicts neither taste nor quality.
• Taste before you commit, and note what you liked so you can buy it again.
• Respect the four enemies — store cool, dark, closed, away from the stove.
• Buy a size you’ll finish — a huge tin goes rancid before a small home uses it.
• Look beyond Italy — Greece and Spain offer superb oils, often better value.

Buying and keeping olive oil: common questions

Can I judge olive oil by its colour?

No. Colour reflects chlorophyll, which depends on the olive variety and ripeness, not quality. Professionals taste from an opaque blue glass precisely so colour cannot mislead them.

What are the four enemies of olive oil?

Age, heat, air and light. Each degrades the oil and pushes it toward rancidity, which is why you store it cool, dark, tightly closed and away from the stove, and use it up reasonably quickly.

How should I store olive oil?

In a cool, dark cupboard, well away from the oven and hob, with the cap firmly closed. Dark glass or a tin helps. Avoid keeping it in a warm, sunlit spot next to the stove.

Does olive oil go off?

Yes. It does not spoil dangerously like meat, but it goes stale and rancid with age, air, heat and light, tasting flat, greasy or crayon-like. Buy recent oil and finish it within a few months of opening.

Is expensive olive oil always better?

Not reliably. Price and quality track each other only loosely. Some superb oils are modestly priced, and the only sure test of whether you’ll like one is to taste it.

Drawn from standard olive-oil storage guidance and tasting practice.