Vegetables
Kale
The one vegetable with a published temperature FIFTY degrees below everything else in its chart.
What it does in fast-moving hot air
A kale leaf is a few cells thick with an enormous surface area for its mass and almost no thermal buffer. At 200°C the edges reach the temperature at which the leaf's sugars and proteins scorch long before the middle of the leaf has dried, so the result is bitter black frills around a limp centre. At 150°C the water leaves slowly enough that the whole leaf dries at roughly the same rate and becomes brittle rather than burnt. It is dehydration with a bit of browning, not roasting, and the time on the chart is what drying takes. It is also light enough to be picked up and blown around by the fan.
Why the cut matters
Kale crisps are the clearest single demonstration in the catalogue that temperature is a property of the food rather than of the appliance. Every other vegetable in the chart this figure comes from is cooked at 200°C. Kale is 150°C, and the reason is entirely about what a leaf is.
Cooking pages
- Kale crisps — Fresh kale for crisps gets eight to nine minutes at 150°C with no oil in one manufacturer's charts for two machines.
This page gives no cooking answer of its own. A food does not have one — a cut, at a thickness, in a state, at a loading, in a particular appliance does. Any figure mentioned above is one manufacturer’s, and the page for the cut says which machine, quantity and state it was printed for, or that the manufacturer named no state.