Corn oil

Yes. Heat it to 175–180 °C, fry in small batches so the temperature does not plunge, and avoid letting the oil smoke; refined corn oil has a high smoke point, around 230 °C.

Keep the bottle tightly closed in a cool, dark cupboard, away from the oven and direct sunlight. Refrigeration is not needed; discard the oil if it develops a stale or paint-like smell.

Yes: its mild flavour suits vinaigrettes when you want the vinegar, lemon or herbs to stand out. Whisk it with vinegar or lemon juice, mustard and seasoning, then drizzle over leafy salads or steamed vegetables.

Most corn oil is extracted from the germ, the small part of the kernel that contains the seed’s stored oil. Commercial oil is usually refined, which gives it a mild taste and makes it suitable for frying.

Usually, yes, in the same quantity. Olive oil brings a more distinct flavour, while corn oil is milder; for high-heat frying, use a refined olive oil rather than a strongly flavoured extra-virgin one.