Choosing a Good Extra Virgin Olive Oil for Cooking

What "extra virgin" is actually telling you

Extra virgin is not a flavour note or a marketing flourish. It is a legal grade: oil pressed from olives by mechanical means alone, without heat or chemical solvents, with free acidity below 0.8 per cent and no faults detected on tasting. Everything else on the shelf sits below it. "Pure" olive oil is a blend of refined and virgin oil, and "light" refers to colour and flavour rather than calories — it has never removed a single one. If a bottle says only "olive oil", you are almost certainly buying something refined and fairly neutral.

This matters because a good extra virgin oil is genuinely versatile. Used with a little thought, one bottle will dress a salad, finish a bowl of beans, roast a tray of root vegetables and fry an onion. You do not need a shelf of oils, just one or two you understand.

Reading the label without falling for the marketing

Turn the bottle over. The back label, dull as it looks, is where the useful information lives.

• Origin: a named country, region or estate tells you far more than "packed in the EU" or "Mediterranean blend", which can mean oil from several countries and several harvests.
• Extraction: look for "cold extracted" or "first cold press". Cool temperatures keep the grassy, peppery compounds intact; heat flattens them.
• Protected names: PDO and PGI status guarantees an oil came from a defined area and was made to a fixed standard.
• Packaging: dark glass or a tin protects the oil from light. A clear bottle parked on a sunny windowsill is already going stale.
• Decoration: "premium", "selection", "finest" and pictures of rustic groves mean nothing at all. Ignore them and read the small print.

Buying a three-litre tin and decanting into a small dark bottle works out cheaper and keeps the bulk of the oil fresh. Just refill little and often.

Harvest dates matter more than best-before dates

Olives are picked once a year, between roughly October and January in the northern hemisphere, so every bottle carries an implicit birthday. A "best before" two years ahead is a legal formality and tells you almost nothing. A harvest date, or at least a harvest year, tells you everything.

Oils are at their most vivid in the first six months and are usually still very good up to about eighteen months from harvest. After that they fade: the green colour dulls, the aroma becomes waxy and the peppery finish disappears. In a British kitchen, where we often buy oil in autumn and keep it for a year, this is the single most useful thing to check.

Peppery or mild? Matching the oil to the job

Early-harvest oils, usually greener in colour, are pungent and sometimes bitter, with a peppery catch at the back of the throat. Late-harvest oils are golden, softer and often buttery. Neither is better; they are simply for different things.

• Peppery, early-harvest: salad dressings, sliced tomatoes, white beans, grilled bread, pesto, hummus, drizzled over soup at the table. Heat blunts the very thing you paid for, so use these raw.
• Mild, buttery, late-harvest: olive oil cakes, sponges, muffins, mayonnaise, and gentle frying where you want the oil to carry flavour rather than shout over it.
• One all-rounder: a medium, fruity oil handles roasting, shallow frying, pasta sauces and everyday dressings perfectly well.

Gentle frying is fine in extra virgin oil. Its smoke point sits comfortably above the temperature you need for softening onions, sautéing potatoes or shallow-frying fish. Just keep the heat moderate and never let it smoke. Save the deep-fat frying for something cheaper.

Using it in a British kitchen without wasting it

Store oil in a cool, dark cupboard, well away from the oven — the bottle beside the hob is the worst place in the house. Screw the cap on properly; oxygen ages oil as surely as light does.

Taste before you commit it to a dish. Pour a small spoonful, sip it, and swallow. Good oil announces itself with fruit, then a warm tickle in the throat. If it tastes flat, greasy or faintly like crayons, it has gone over and belongs in the bin rather than your vinaigrette. If an oil is too aggressive for a cake but too delicate for a salad, don't force it: use it for roasting and buy better next time.

Herbs from the garden, and one safety rule worth knowing

The easiest way to make a decent oil taste like an exceptional one is to grow the herbs that go with it. Rosemary, thyme, bay, oregano and lemon thyme all thrive in a pot on a sunny windowsill or a sheltered patio, and all cope with British weather far better than basil does.

For a quick herby oil, warm a few sprigs of dried or fresh rosemary and a bay leaf gently in oil over the lowest heat for ten minutes, cool, then strain and use within a week. Keep it in the fridge. If you blend fresh soft herbs such as basil or parsley into oil, use it that day or freeze it in ice-cube trays — it will not keep.

One firm rule: never keep fresh garlic or fresh chillies submerged in oil at room temperature. They can harbour bacteria that thrive in an oxygen-free environment, and the risk is real. Use dried garlic or chilli flakes instead, or make a fresh garlic oil and refrigerate it, using it within a few days.

Get those basics right and your kitchen garden, a decent tin of oil and a harvest date will take you a long way — long before you need anything fancy.