Instructions

1. Thicken the chilli before it goes near a tray: a spoonful of cornflour, stirred in and cooked out for a minute. Anything that runs when the tray is tilted will run off the sheet, and the starch holds the fat in suspension rather than letting it separate as the leather sets.
2. Mash the meat down to grains about the size of rice. A lump of mince dries into a hard nugget that never fully comes back in a camp bowl.
3. Leave the beans whole for some body or halve them for speed. A whole bean holds water at its centre, so whole beans mean a longer run and you should expect it.
4. Work in single-cup lots and spread each as one strip on a drying sheet. Measuring now is what turns this into portions rather than a bag of guesswork.
5. Run a meatless chilli at 57 °C and one carrying meat, dairy or oil at 68 °C, for 9 hours. The higher figure is a safety setting, not a faster one.
6. With a meat chilli, lift the leather off the drying sheet onto bare mesh as soon as the top has set. The heat forms a skin otherwise, and a sealed skin keeps the middle wet for the rest of the run.
7. It is finished when a piece snaps and crumbles in the hand with no give at all. Press a fingernail into the thickest part of the strip rather than the edge.
8. Crumble each leather into its own bag. Vacuum-sealed with an oxygen absorber a meat chilli holds a month in the pantry, six in the fridge and a year frozen; a meatless one keeps for years the same way, and a plain zip bag cuts all of that to about a month in the fridge.
9. To eat it, pour boiling water into the bag to just cover, squeeze it around, seal it and wait five minutes.