Instructions

1. Buy hearts packed in brine rather than oil, and read the label rather than trusting the picture. Oil works its way between every leaf layer, and oil does not leave in a dehydrator.
2. Rinse them under running water and work a thumb between the leaves. Brine hides in the folds, and what stays behind dries into salt crystals that taste of nothing but salt.
3. Press the rinsed hearts between two tea towels. They are soft enough to squash, which is exactly what you want — water that comes out under the towel is water the machine does not have to lift.
4. Chop them into pieces about 6 mm across. A heart is layered like an onion, and a larger piece keeps its layers pressed shut.
5. Loosen those layers with your fingers as you lay the pieces out. A piece that opens like a fan dries in half the time of one that stays closed.
6. Dehydrate at 57 °C for 7 hours. They shrink to about a third and go deep khaki, which is normal for a vegetable that was cooked once before it ever reached you.
7. A finished piece is hard and light for its size and crumbles at the edge under pressure. If the innermost leaf is still leathery, that piece was cut too thick and wants another hour.
8. Jar them once cold and keep them dark for up to a year. Cover them with warm water for ten minutes to use, and hold on to that water — it belongs in whatever you are cooking.