Should I bake cakes with the fan on?

A fan does not add heat, it moves it. That improves evenness dramatically — the whole cavity ends up close to the same temperature, which is why fan ovens can bake three trays at once — and it increases the rate at which heat reaches the food, which is why the temperature is reduced. The cost is airflow across the surface, which dries it, sets a skin earlier, and can push a light batter around before it sets. That trade-off is the whole decision.

What you'll need

• An oven thermometer (optional)

Step by step

1. Work out which settings your oven actually has.Fan only, conventional (top and bottom elements, no fan), fan-assisted (elements plus fan), and grill. They behave differently and the symbols are not always obvious — see `decode-oven-symbols`.
2. Apply the 20°C reduction, then verify it.A recipe at 180°C conventional becomes about 160°C fan. That figure is a manufacturer's convention, not a physical constant, and ovens vary. If your bakes come out dry at the reduced temperature, reduce by 15°C instead and extend the time.
3. Use fan when evenness or capacity matters.Trays of biscuits, batches of rolls, roast potatoes, pastry, and anything on two or three shelves at once. Fan is genuinely better here and it is why the setting exists.
4. Use conventional for delicate and long bakes.Whisked sponges, soufflés, meringues, custards, rich fruit cakes. Anything where a dried skin, a blown surface or a fast-set crust is a problem does better in still air.
5. Watch the timing as well as the temperature.Fan bakes faster even at the reduced temperature — often 10 to 15 per cent faster. Start checking earlier than the recipe says.
6. Expect less colour.Fan-baked cakes brown less and dry more. A brush of milk before baking, or the last few minutes with the fan off, restores the colour if it matters.
7. Check the real temperature either way.Both settings can be twenty degrees out. A thermometer settles whether you have a fan problem or an oven problem. See `check-oven-temperature`.

Tips

• Gas ovens have real heat zones — hotter at the top — and no fan. Recipes written for gas assume you know that and use the shelf position accordingly.
• Some ovens have a 'pastry' or 'baking' function that runs the fan at low speed with more bottom heat. It is genuinely useful for tarts and pizza.
• Air fryers are small fan ovens. They bake small cakes and biscuits perfectly well with the same reduction and much shorter times.
• If your recipe gives both temperatures, use the one it gives rather than converting. If it gives only one, check which — recipes from UK books usually state fan separately.

Common mistakes

• Baking a conventional recipe at its stated temperature on fan — You are effectively 20°C hot, which burns edges, dries crumb and sets crusts before cakes finish rising.
• Assuming fan is always better because it is the newer setting — For meringues, soufflés and delicate sponges, still air is the correct environment and the fan actively works against you.

If it doesn't work