Three ways to salt a ferment
Dry salting — for sauerkraut and kimchi — mixes salt straight into the vegetables, which release their own juice. The salt is a percentage of the vegetable weight: 1,000 g of cabbage at 2% needs 20 g of salt.
Brine — for cucumber pickles and whole vegetables — covers the vegetables in salted water. The salt is a percentage of the water weight: 1 L of water at 3.5% needs 35 g of salt. Some recipes — olives and pickled walnuts especially — give the strength as a percentage of the finished brine instead (salt ÷ water + salt): a “10% brine” there is 100 g of salt in 0.9 L of water. Choose “Total brine” to match; at strong brines the difference is about 10%.
Equilibrium brine weighs the vegetables and the water together and salts the total, so once the salt evens out the whole jar sits at the chosen percentage: 800 g of vegetables plus 0.2 L of water at 2.5% needs 25 g of salt.
Brine strength at a glance
Conversions only, not recommendations — follow a tested recipe for the strength to use.
| Salt, % of water | Salt per litre |
|---|---|
| 2% | 20 g |
| 3% | 30 g |
| 3.5% | 35 g |
| 5% | 50 g |
| 10% | 100 g |
Why salt by weight?
Salt crystals vary so much in size that a spoonful of one brand can weigh twice as much as another. Going by the manufacturers' labels, a teaspoon of Diamond Crystal kosher salt weighs about 2.8 g, Morton kosher about 4.8 g and table salt about 6 g. A recipe written in spoons can therefore be twice as salty — or half as salty — depending on the box in your cupboard. Weighing removes the guesswork.
How strong can a brine be?
Water can only dissolve about 36 g of salt per 100 g at room temperature, so a brine above 36% of the water's weight leaves salt undissolved. The calculator stops you there. Fermentation brines are far weaker than that — typically a few percent.
Follow a tested recipe
Salt holds back spoilage while the good bacteria get going. Too little can leave a ferment soft, slimy or spoiled; too much can stop it. This calculator gets the weight right for the percentage you choose — use a tested recipe to choose it, and keep the vegetables under the brine.