Instructions

1. Cut the beef with the grain into long thick strips and keep them all much the same girth. Biltong is chewed along its fibres, and a strip cut across the grain falls into crumbs in the hand.
2. Stir the vinegar, lime juice and zest together before any dry spice goes near them. Zest oil needs liquid to carry it, and tipped straight onto salt it simply clumps.
3. Marinate in glass or ceramic, never metal. This sits in acid overnight and a reactive bowl gives it a tinny edge you cannot season out.
4. Refrigerate for twelve to twenty-four hours and turn the strips twice, so the ones at the bottom are not the only pieces lying in liquid.
5. Lift the beef out and blot it, leaving the rosemary and thyme clinging where they are. Surface wet is what you want gone; the herbs are the part you paid for.
6. Hang each strip from its own hook with a finger of air around it. This is curing by airflow rather than heat, and two strips touching stay grey and damp where they meet.
7. Hold it at 25 °C for 72 hours for a wet, fatty biltong. For a drier biltong add another 24 hours at a time until it suits you. Squeeze a strip at its thickest point: soft in the middle gives you a pink, moist biltong, and firm the whole way through with no give means it comes down.
8. Let the strips sit at room temperature for an hour, then slice across the grain into thin shavings. Whole strips keep better than cut ones, so shave only what is about to be eaten.
9. Keep it in a paper or cloth bag in the cupboard rather than a sealed jar. Biltong is deliberately left a little moist and it will mould behind glass; bagged, it holds a month, and it freezes for six.