Lacto-Fermentation Salt Calculator

Salt is what makes lacto-fermentation safe. It suppresses pathogens and mold while lactobacillus — the bacteria that acidifies the ferment — survives and thrives. As the pH drops, even salt-tolerant organisms get out-competed.

Salt weight = vegetable weight × salt percentage / 100

The right percentage depends on what you are making:

2%: classic sauerkraut, most mild European-style ferments. Enough to draw water from the cabbage and prevent surface mold without making the finished product unpleasantly salty.

2.5%: kimchi and Korean-style ferments. Traditionally the cabbage is salted heavily first (10–15%) and rinsed, then the finished ferment settles around 2–3% net salt.

3%: whole brined vegetables — pickles, peppers, green beans, carrots. Here the vegetables ferment in brine rather than their own expressed liquid, so the salt applies to the water weight.

5%: olives, longer-term room-temperature ferments. Higher salt slows fermentation significantly and extends shelf life without refrigeration.

Always use non-iodized salt. Iodine is added to table salt specifically to kill microorganisms — it kills lactobacillus right along with everything else. Use kosher salt, sea salt, or pickling salt.

Weigh your salt rather than measuring by volume. Granule size varies enormously: 1 teaspoon of table salt weighs about 6 g, while 1 teaspoon of Diamond Crystal kosher salt weighs about 3 g. Weighing eliminates the guesswork.

Temperature affects fermentation speed. At 65–75°F, 2% sauerkraut takes 4–6 weeks. At 80°F it can finish in under 2 weeks but may develop sharp off-flavors. Ferment cooler and slower for a more complex result.