Quick answer: Nine times out of ten it’s overcrowding, surface moisture, or not enough oil — rarely the machine itself.
The Most Common Culprit: Overcrowding
Hot air needs to actually reach every surface of the food to crisp it. A packed basket blocks that airflow, and food closer to the bottom or middle ends up steaming in its own moisture instead of crisping.
Fix: cook in a single layer with a bit of space between pieces. Two smaller batches almost always beat one packed one. Shake or flip halfway through so both sides get exposed.
Surface Moisture Is the Sneaky One
Water on the surface of food has to evaporate before browning can even start — so wet food effectively steams for the first few minutes before it can crisp at all.
Fix: pat food dry with kitchen paper before seasoning and cooking. This applies to fresh food, and it’s worth doing with frozen food too — don’t rinse frozen chips or nuggets before air frying.
Oil: Not Too Little, Not Too Much
A light coating of oil genuinely helps browning and crisping — going completely oil-free often leaves food pale and a bit leathery rather than crisp. But too much oil creates a greasy film, softens the result, and can contribute to smoking (see our guide to air fryer smoking).
Fix: a light spray or a teaspoon or two, tossed through rather than pooled at the bottom. If you want exact amounts for what you’re cooking, the Oil Usage Calculator does the maths for you.
Preheat First
A preheated basket starts crisping food the moment it goes in. Skip preheating and food heats up gradually, which gives moisture more time to build up before browning gets going.
Give It a Finishing Blast
It’s easy to stop the moment food is technically cooked through — but an extra minute or two once it’s done often makes the difference between “fine” and genuinely crispy. This is especially worth doing for reheated fries, nuggets, leftover pizza, and roast veg.
Still Not Crispy?
If you’ve tried all of the above and it’s still not working, it’s worth considering uneven hot spots — even good air fryers have them, and the underside of food often gets less exposure than the top. For a more tailored diagnosis based on exactly what you’re cooking, try the Crispiness Adjuster.
Frequently Asked Questions
Do I need oil at all?
Not strictly, but a light coating makes a noticeable difference to browning and texture. Oil-free results tend to be more “dried out” than genuinely crispy.
Why is frozen food less crispy than fresh?
Ice crystals on the surface add extra moisture that has to cook off first. Don’t rinse frozen food before air frying, and consider a minute or two longer than a fresh-food recipe would need.
Does it matter if I have a basket-style or oven-style air fryer?
Both work on the same principle (rapid hot air circulation), but oven-style models sometimes have less concentrated airflow. The same fixes apply either way — overcrowding and moisture are still the main issues.
