Temperatures and times, and why they decide the batch

Drying is not cooking. The aim is to remove water slowly enough that the inside of a slice keeps up with the outside. Almost every failed batch comes from breaking that one rule.

The working ranges

• Herbs and leaves: 35–40 °C. Higher and the volatile oils that carry the flavour leave with the water.

• Fruit: 55–60 °C. Colour and vitamin content survive; above about 65 °C they do not.

• Vegetables: 50–60 °C, depending on how much water they start with.

• Meat: 68–70 °C, which is a food-safety floor rather than a preference.

What case-hardening is

Push fruit to 75 °C to save four hours and the surface dries into a shell before the centre has given up its water. The slice feels done. Sealed in a bag, the trapped moisture redistributes over a week or two and the batch spoils from the inside.

This is the single most expensive mistake in dried fruit, because it is invisible at the moment you decide the batch is finished.

Thickness does more than time

Even thickness matters more than thin. A tray of 5–6 mm slices finishes together; a tray of mixed thicknesses finishes three times, and you either pull it early and spoil the thick pieces or run it long and turn the thin ones to dust.

Lay pieces flat with a little space between them. Overlapping slices trap moisture and dry unevenly.

How to tell it is actually done

Tear a thick slice in half rather than judging by the surface. Fruit should be leathery and pliable with no wet centre; if it feels tacky and cool it needs another hour. Vegetables should snap. Let a piece cool first — everything feels softer warm, and more than one batch has gone back in that did not need to.