Extra virgin olive oil

Yes. Use it for roasting, sautéing and shallow-frying; for a gentler flavour, choose a milder-tasting bottle. Keep the oil below its smoking point: if it smokes, take the pan off the heat and let it cool before using it again.

Look for a harvest date as well as a best-before date, and choose a bottle stored away from light. Fresh oil can smell grassy, fruity or like green tomato; a waxy, stale or crayon-like smell suggests it has deteriorated.

Keep the bottle tightly closed in a cool, dark cupboard, away from the oven and direct sunlight. Use it within a few months of opening for the freshest flavour; refrigeration is unnecessary and can make the oil cloudy or firm.

It is central to Mediterranean cooking: drizzle it over tomato salad, grilled vegetables or soup, or use it in pesto, hummus and vinaigrette. For a simple dressing, whisk it with lemon juice or vinegar, mustard and a little salt.

Often, yes: use about three-quarters as much oil as butter by weight, since butter contains water as well as fat. It works especially well in cakes and quick breads, but its fruity flavour may come through.

Extra virgin oil is mechanically extracted and must meet strict standards for acidity and sensory quality; ordinary olive oil is usually refined oil blended with some virgin oil. Extra virgin has a more pronounced aroma and flavour, while refined oil is milder.

Yes. Heat, light and air gradually dull its fresh, peppery or fruity notes. If it smells rancid, like old nuts, wax or crayons, or tastes unpleasantly stale, discard it rather than masking it in a dish.

You can, but it is rarely useful: chilling or freezing may make it cloudy or solid, and it returns to liquid at room temperature. A sealed bottle in a cool, dark cupboard is easier to store.