Fermentation Brine Calculator (Reference)

The one page I wish I had taped inside a cupboard door for the first twenty years. Salt is the only number in vegetable fermenting you never guess, and there are exactly two ways to compute it depending on whether the vegetable makes its own brine or sits in one you mixed. Everything else is preference.

Ingredients

A digital scale — the only mandatory purchase

• Canning or pickling salt (or any pure salt without anti-caking agents)
• Water, dechlorinated if your utility uses chloramine

Directions

1. Key ingredients

A scale. That is genuinely it.

1. METHOD 1 — SELF-BRINING (percentage of VEGETABLE weight). For shredded or sliced vegetables you salt directly and that release their own liquid: sauerkraut, kimchi, shredded roots. Add no water.

salt = vegetable weight x target percentage

1. 900 g shredded cabbage at 2.25% = 900 x 0.0225 = 20 g salt.
2. METHOD 2 — ADDED BRINE (percentage of the WATER). For whole or large-cut vegetables that cannot be crushed: cucumbers, beans, cauliflower, carrots, peppers, garlic.

salt = water weight x target percentage

1. 2000 g (2 litres) of water at 5% = 100 g salt. Water is easy: 1 litre = 1000 g.
2. THE PERCENTAGES:
3. Sauerkraut 2.25% self-brine (2.0 low end, 2.5 for a warm room)
4. Kimchi 2–3% on the cabbage, brine-then-rinse, then paste
5. Cucumber pickles 5–8% added brine
6. Carrots, beans, cauliflower 3–3.5% added brine
7. Radish, turnip 2.5–3% added brine
8. Peppers / hot sauce mash 3–5%
9. Whole garlic 3%
10. Beets 2.5–3% (very sugary, ferments fast)

Salsa-style mixes 2.5–3% self-brine

1. THE THREE LEVERS: more salt = slower, firmer, keeps longer, saltier. Cooler = slower and far more aromatic (55–65 °F makes the best kraut; above 80 °F cucumbers go to mush). More time = lower pH and more sourness. Stop where you like it.

Notes

WHY WEIGHT AND NOT VOLUME. Salt crystals differ enormously in bulk density: a tablespoon of fine canning salt is roughly 17–19 g, Morton kosher about 14–15 g, and Diamond Crystal about 9–10 g. A recipe written for fine pickling salt and made with Diamond Crystal delivers a bit over HALF the intended salt — enough to take a 2.25% kraut down to about 1.25%, which is below where I would be comfortable. This one substitution accounts for a great many mushy, off-tasting ‘I followed the recipe’ first batches.

NCHFP IS EMPHATIC on the direction that matters: do not attempt to make sauerkraut or fermented pickles by cutting back on the salt required. Salt handicaps spoilage organisms for the days before the acid takes over — it is a safety control, not a seasoning.

THE IODIZED-SALT PANIC IS OVERSTATED. The sourced NCHFP objection to table salt is that non-caking material ‘may make the brine cloudy’ — appearance, not culture death. Use canning salt because it is cheap and pure and removes the question, but correct weight of the wrong salt beats guessed volume of the right one every time.

NEVER USE CURING SALT. ‘Pink salt’ means Himalayan salt to a home cook and sodium NITRITE to a charcutier. Prague Powder / Cure #1 is dyed pink so you do not make this mistake and it is a real poisoning risk at kraut quantities.

WATER: chlorine dissipates if you leave water out overnight; CHLORAMINE does not and boiling will not remove it — use a carbon filter. Hard water is generally helpful (calcium firms pectin). Never use softened water, which swaps calcium for sodium.

A SUBTLETY: vegetables contain water too, so a 5% brine around cucumbers equalises to a much lower overall concentration. That is why cucumber percentages look alarming next to kraut’s — they are not comparable numbers.