Food is not crisping

What is happening

Crisping is dehydration of a surface layer. Anything that stops water leaving the surface, or puts water back onto it, stops the food crisping — and in a small chamber the commonest cause by a wide margin is simply having put too much in.

Narrow it down

Each of these has an answer you already know, and each one rules something out.

1. Was the food in a single layer with gaps between the pieces?

   • Yes
   • No — it was piled up or the pieces were touching — This is the answer about eight times out of ten.

2. Is there liquid in the bottom of the basket at the end?

   • Yes — The food has been steaming in its own moisture.
   • No

Why it happens

Commonest first. It is almost always the boring one, and a page that walks you through the exotic causes before the obvious one has given you a longer path to a fixed dinner.

1. Most common

   The basket is overfilled

   One manufacturer states it plainly: if the basket is overfilled, food will cook unevenly. The mechanism is that steam leaving the food has nowhere to go, so it condenses back onto the surfaces it just left, and the buried faces never get dry air at all.

   What to do

   • Cook it in two batches rather than one
   • Leave gaps between the pieces

2. Common

   There is no oil on food that needs some

   Oil conducts heat into the surface and raises the temperature the surface can reach. Factory-fried foods carry their own; raw vegetables, hand-cut chips and lean meat do not, and a manufacturer in this catalogue recommends a small amount specifically because it makes food crisper.

   What to do

   • Toss the food in a small amount of oil

3. Common

   The food went in wet

   Every minute spent evaporating surface water is a minute not spent browning. Frozen food carries surface ice, washed vegetables carry rinse water, and marinated food carries a wet coating — all three delay crisping rather than preventing it.

   What to do

   • Dry the surface before it goes in
   • For hand-cut chips: soak, then dry thoroughly

4. Occasional

   The temperature is below the browning range

   Below roughly 150°C the surface dries without browning appreciably, which produces something dry and pale rather than crisp. It is the correct setting for kale crisps and the wrong one for chips.

   What to do

   • Move up into the browning range

5. Occasional

   The food cannot crisp

   Courgette, peppers, mushrooms and tomatoes are mostly water in soft structures with no starch and little sugar. They blister and brown; they do not become crisp, and expecting them to is a misdiagnosis rather than a fault.

   What to do

   • Check whether the food can crisp at all

The fixes in full

Cook it in two batches rather than one

Two batches of a properly spaced single layer beat one crowded batch by a wide margin, and the second batch is faster because the machine is already hot. This is the single highest-value change on this page.

Trade-off: It takes longer in total, and the first batch needs somewhere warm to sit.

You will know it worked when: The pieces are dry and coloured on every face rather than pale where they touched.

Leave gaps between the pieces

Single layer, not touching, is the loading condition almost all published cooking times assume. Anything else is slower than the figure you are following.

Dry the surface before it goes in

Kitchen paper on meat and fish, a clean tea towel on washed vegetables. Two published chart rows in this catalogue give 'pat dry' as the entire preparation instruction, for prawns and scallops.

For hand-cut chips: soak, then dry thoroughly

The published instruction is to soak raw chips in cold water for at least thirty minutes to remove surface starch, then pat them dry — with a footnote that the drier the chips, the better the result.

You will know it worked when: The chips do not stick to each other in the basket.

Toss the food in a small amount of oil

A manufacturer in this catalogue recommends a small amount of oil specifically to make food crisper, and caps it at 30ml. Toss it in a bowl rather than spraying the basket — one manual warns that aerosol propellants can damage the coating.

Trade-off: It is no longer an oil-free method, though 15ml across a basket is a fraction of shallow frying.

Move up into the browning range

Most published air-fry figures for things that should be crisp sit at 180-200°C. If you are below that for something that is meant to be crisp rather than dried, that is the reason.

Trade-off: Fatty foods smoke more at higher temperatures, and sugary ones burn.

Check whether the food can crisp at all

A cooked pepper is soft and blistered. A courgette is browned and slack. Neither becomes crisp in any appliance, and the cooking page for each says so before it gives a time.

Evidence and confidence

Foods this affects

• Frozen chips
• Homemade chips
• Chicken wings
• Courgette sticks

Equipment that bears on this

• Silicone basket insert — Works, but costs you results — The most-sold air fryer accessory and the commonest way to make an air fryer cook worse. It works; it costs you the thing you bought the machine for.
• Multi-level rack — Useful for a specific job — It adds a level. It does not add capacity, and one manufacturer states plainly that only one level may be used in air-fry mode.
• Oil sprayer — Genuinely useful — Good for coating food evenly with very little oil. At least one manufacturer forbids spraying it into the chamber, and aerosol cooking sprays damage non-stick coatings.

Related problems

• Chips and fries come out soggy
• Food cooks unevenly