Instructions

1. Trim every visible seam of fat and silverskin from the flank before slicing. Silverskin will not soften and a strip with a band of it through the middle pulls apart in the wrong place.
2. Cut the beef into 6 mm strips across the grain for a jerky that breaks cleanly, or along it if you want the long chew that deli pastrami has.
3. Whisk the soy, Worcestershire, sugar, lemon juice and cayenne together before the meat goes in, and leave the whole seeds out. Dissolving the sugar first is what stops it sitting in a sludge at the bottom of the dish.
4. Marinate the strips in the fridge overnight, turning the bag once if you remember. The salt in the soy and Worcestershire is doing more than flavouring — it draws water out of the surface and gives the drying a head start.
5. Lift the strips out and let them come back to room temperature on a rack, then press the pepper, coriander and mustard seeds onto the wet faces with the flat of your hand. Seeds only scattered on will be in the bottom of the bag by the time you eat them.
6. Dehydrate at 65 °C for 8 hours, seeded side up. Begin checking about two-thirds of the way in, because thinner strips at the edge of the tray will be finished well before the ones in the centre.
7. Bend a cooled strip into a right angle: it should crack along the fold and hold together rather than snapping in two or folding limply. Judge it cold — a warm strip always feels drier than it is.
8. Store the jerky in a sealed bag or jar and eat it within two weeks at room temperature, or a month in the fridge. Without a vacuum seal there is enough moisture left in a proper jerky to grow mould, so look at it before every handful.