Instructions

1. Sort the peppers and discard any with a soft shoulder or a split in the skin. Chillies rot from the stem end down, and one going over will take the tray with it.
2. Wear gloves from here on and keep your hands away from your face. Capsaicin does not wash off with water, and a batch of chillies is more than enough to make that a lesson you only learn once.
3. Halve the thick-walled peppers lengthways and leave the thin-walled ones whole. A jalapeno has flesh several millimetres deep that will not dry through an intact skin, while a cayenne or a bird's eye is thin enough to dry as it is.
4. Scrape out the seeds and pale ribs if you want less heat, since that is where most of it sits. Leaving them in is not wrong, it just makes a hotter powder than people expect.
5. Lay them cut side up with plenty of space between them and run the machine somewhere ventilated, ideally not in the kitchen. Chillies at 63 °C put out a fume that will have the room coughing.
6. Dehydrate at 63 °C for 8 hours, longer for the halved thick-walled ones. Colours deepen as they go — red goes almost to brown and green to a dull olive.
7. A finished pepper is papery and rattles when you shake the tray, and a pod snapped in half breaks rather than folding. Let them cool first, because chilli skin feels leathery while warm even when it is finished.
8. Keep whole pods in an airtight jar in a dark cupboard for a year. If you grind them, let the dust settle in the blender before you open the lid, and use the powder within six months — it loses colour and smell far faster than the whole pods do.