Salting fish: How long and how much?

Why does this happen? / What's behind it?

Fish has a much finer, more delicate tissue structure compared to meat – which means salt works its way through much faster. Osmosis draws water out of the fish flesh, salt moves in, and bacteria don't stand a chance. At the same time, the protein structure changes slightly, giving the flesh that characteristic firmer texture.

The thickness of the piece is the decisive factor. A 2 cm thick trout fillet is fully cured after 12 hours. A full salmon side at 5–6 cm thickness needs closer to 20–24 hours. Working by feel risks either under-curing (food safety issue!) or ending up with a salt brick instead of fish.

There are two methods: dry curing (salt directly on the fish) and wet curing (brine). For most home setups, dry curing is simpler, more controllable, and delivers better results – so that's what we're focusing on here.

How to fix it / How to do it right

• Determine the amount: 30–40 g of salt per kg of fish. If you prefer milder, go with 30 g; if you want it stronger or plan to smoke it, use 40 g. Always weigh it, never eyeball it.
• Rub salt evenly: Apply salt evenly on all sides of the fish – especially in belly folds or inside whole fish. The skin needs a little more since it's less permeable.
• Keep it cold: Place the fish in a tray (it will release liquid), cover it, and refrigerate at 2–4 °C. Never cure at room temperature.
• Time based on thickness:

- Up to 2 cm thick: 8–12 hours

- 2–4 cm thick: 12–18 hours

- Over 4 cm thick: 18–24 hours

• Rinse & dry: After curing, rinse the fish thoroughly under cold water, pat dry, and let it air-dry uncovered in the fridge for 1–2 hours before smoking (to form the pellicle).

Conclusion

30–40 g of salt per kg, 12–24 hours depending on thickness, always in the fridge – stick to this and you've already nailed the most important part of curing fish.