Oil

For high-heat frying, choose a refined oil labelled for frying; it is usually more suitable for sustained heat than an unrefined oil. Save oils with a strong flavour, such as extra-virgin olive oil, for dressings or gentler cooking.

Aim for 170–180 °C: food should sizzle as it goes in, but the oil should not smoke. A thermometer makes the temperature easier to control; add food in small batches so the oil does not cool too much.

Let it cool, then strain out crumbs before storing it in a clean, sealed container. Reuse it only if it still smells fresh and looks clear; discard it if it is smoky, foamy, unusually dark or smells stale.

Keep the bottle tightly closed in a cool, dark cupboard, away from the oven and sunlight. Refrigeration can make some oils cloudy or solid, but they usually clear again when brought back to room temperature.

Smell a small amount: rancid oil can smell like old nuts, wax or paint, and may taste bitter or stale. If the smell or taste is unpleasant, do not use it, even if it looks normal.

No. Let it cool, then pour small amounts into a sealed, non-recyclable container for disposal with household rubbish; follow local guidance for larger amounts. Wipe greasy pans with kitchen paper before washing them.

“Oil” is a broad name for fats pressed or extracted from plants or other sources; olive oil is specifically made from olives. Their flavour and best uses differ, so check the bottle for the oil’s source and whether it is refined.