Parchment, foil, and what is safe in the basket

This is the one guide here with an actual safety warning in it that is not about food poisoning.

The fire risk, stated plainly

An air fryer’s fan moves air fast enough to lift a sheet of baking parchment off the basket floor and into the heating element above it.

Paper against a glowing element is a fire. Not smoke, not a smell — a fire, inside a plastic-bodied appliance, on your worktop.

This is not a theoretical hazard invented for a warning label. It happens routinely, and it happens for a specific and avoidable reason: people preheat with the liner already in place.

The one rule

Parchment goes in with the food on top of it, never before.

That is the whole thing. Food weighs the paper down. An empty basket with a loose liner in it, running at 400°F with the fan going, is the failure case.

Related rules that follow from it:

• Cut it to size. It should not extend up the sides of the basket where airflow can catch an edge. Perforated air fryer liners are sold for this and they are a reasonable purchase if you bake often.
• Never kitchen towel. Lighter than parchment and even easier to lift. There is no situation where paper towel belongs in a running air fryer.
• Do not leave a liner in between batches while the machine sits empty and hot with the fan running.

When you actually need parchment

Less often than you might think. It is worth using when:

• Baking. Cosori specifically calls for parchment with cookies. Batter sticks and burns onto the basket.
• Anything with a melting, sugary filling. Cinnamon rolls leak syrup that scorches on contact with the hot basket floor.
• Small or crumbly things that would fall through the mesh.

It is worth not using when you want crisp. Parchment blocks the airflow to the underside of the food, which is the one thing an air fryer does that an oven tray does not. Chips on parchment are chips cooked on a tray.

Foil

Foil is safe from a fire perspective — it is heavy enough not to fly and it handles the temperature without trouble.

The trade-off is airflow. Covering the basket floor with foil turns your air fryer into a small conventional oven, because air can no longer reach the underside of the food.

Use it deliberately, for the two cases where the trade is worth it:

• When you want to trap heat rather than crisp. Cosori’s frozen burrito instruction is foil-wrapped at 320°F, precisely because the goal is getting heat into a dense frozen core without turning the tortilla to leather. Then unwrap for the last few minutes.
• When something would otherwise weld itself to the basket — a sticky glaze, a marinade with sugar in it.

Do not use foil with acidic food. Tomato, citrus and vinegar react with aluminium, pit the foil and give the food a metallic edge.

Never let foil touch the element, and never line the drawer under the basket, which blocks the air path the machine depends on.

Other things people ask about

Silicone liners and moulds. Safe, reusable, and heavy enough not to fly. Same airflow trade-off as parchment. Good for cupcakes, where paper cases are light enough to be blown over.

Glass and ceramic. Only if the dish is rated for the temperature you are using — check the base. Avoid thermal shock: no cold dish straight into a hot machine, and nothing straight from the machine onto a cold wet surface.

Metal tins and racks. Fine, as long as they clear the element and do not block the airflow entirely.

Ceramic plates from the cupboard. Usually fine on temperature, but check for metallic trim or gold rims, and remember that anything you put in reduces the air space the machine needs.

Why the airflow argument matters more than people think

Every liner decision is a trade against the one thing that makes an air fryer different from an oven: air reaching the underside of the food.

On an oven tray, the bottom of a chip sits against hot metal and stews in its own steam. That is why oven chips have a soft side. In a perforated basket, the fan reaches underneath, the steam is carried away, and the chip crisps all round.

Put a solid liner in — foil, parchment without holes, a silicone mat — and you have rebuilt the oven tray inside your air fryer. The food still cooks, but you have given up the reason you bought the machine.

This is why perforated liners exist and why they are worth the small premium if you use liners often. It is also why the answer to “should I line the basket?” is usually no, and specifically yes only for batter, melting sugar, and things small enough to fall through.

Quick reference

Item	Safe?	The catch
Parchment, cut to size, food on top	Yes	Never in an empty preheating basket
Parchment, loose or empty basket	No	Fire risk — lifts into the element
Perforated air fryer liner	Yes	Best compromise if you line often
Kitchen towel	No	Lighter than parchment, same risk
Foil, under food	Yes	Blocks airflow beneath the food
Foil, lining the drawer below the basket	No	Blocks the air path entirely
Foil, with acidic food	Avoid	Reacts with aluminium, metallic taste
Silicone liners and moulds	Yes	Same airflow trade as parchment
Oven-safe glass or ceramic	Yes	Check the rating; avoid thermal shock
Metal tins and racks	Yes	Must clear the element
Anything touching the element	No	Fire risk regardless of material

Cleaning, briefly

The reason liners are tempting is cleaning, so it is worth saying: the drawer matters more than the basket. Rendered fat pools there — six rashers of bacon will produce a surprising amount — and on many models it sits directly over the element, where it smokes on the next use.

Pour it off between batches. That single habit does more for the smell of your kitchen than any liner will.

The summary

Parchment: yes, cut to size, food on top, never in an empty preheating basket. Foil: yes, but understand you are giving up the airflow you bought the machine for. Paper towel: never.