Lacto-Ferment Salt Calculator
Lacto-fermentation relies on salt to create an environment where lactobacillus bacteria thrive and harmful bacteria cannot. The salt percentage determines the speed of fermentation, the level of sourness, and the safety of the end product. Too little salt risks spoilage; too much inhibits beneficial bacteria and produces an unpleasantly salty product. This calculator supports both wet brine (for whole vegetables like cucumbers) and dry salt (for shredded vegetables like cabbage for sauerkraut). Enter the water or vegetable weight and choose your desired salt percentage, and the calculator returns the precise salt amount in grams and teaspoons.
Salt percentage formula
Salt (g) = weight (g) * salt_percentage / 100
Example: 1,000 g water at 2% = 1,000 * 0.02 = 20 g salt
Fine sea salt: 1 tsp = approx. 6 g
Kosher salt (Diamond Crystal): 1 tsp = approx. 3 g
Kosher salt (Morton): 1 tsp = approx. 4.8 g
Always measure salt by weight for precision. Teaspoon equivalents are approximate and vary by salt brand and grind.
Fermentation safety tips
- Keep vegetables fully submerged below the brine at all times. Use a weight or zip-lock bag filled with brine to hold them under.
- Use a clean jar and clean hands. Sterilization is not required, but cleanliness is.
- Ferment at room temperature (65-75 F) away from direct sunlight.
- Kahm yeast (white film on top) is normal and harmless. Fuzzy mold in colors other than white indicates spoilage - discard that batch.
- Transfer to cold storage when the desired sourness is reached (taste daily after day 3-5).
Lacto-fermentation: frequently asked questions
What percentage salt brine should I use for lacto-fermentation?
A 2-3% salt brine (by weight of water, or total weight) is standard for most vegetables. 2% is common for mild, quick ferments like sauerkraut and pickled cucumbers. 3% is safer for warmer environments and produces a more sour, tangy result. Never go below 1.5%, as lower salt concentrations may not inhibit harmful bacteria.
What is the difference between dry salt and wet brine fermentation?
Dry salting (for sauerkraut and kimchi) means mixing salt directly with shredded vegetables and massaging until they release liquid to form their own brine. Wet brine (for whole vegetables like cucumbers and carrots) means submerging vegetables in a pre-made salt solution. This calculator covers both methods.
Can I use iodized salt for lacto-fermentation?
Non-iodized salt is strongly preferred. Iodine is antimicrobial and can inhibit the lactobacillus bacteria needed for fermentation, resulting in slower, inconsistent ferments. Use non-iodized sea salt, kosher salt, or pickling salt.
How long does lacto-fermentation take?
At room temperature (68-75 F), most vegetable ferments are ready in 3-14 days. Faster at warmer temperatures, slower at cooler ones. Taste daily after 3 days - fermentation is complete when the desired sourness is reached. Once you are happy with the flavor, move to cold storage (refrigerator) to stop further fermentation.
Is it safe to ferment vegetables at home?
Yes, lacto-fermentation is one of the safest food preservation methods when done correctly. The salt inhibits harmful bacteria while allowing lactobacillus to thrive. The acid (lactic acid) produced further prevents pathogens. The National Center for Home Food Preservation has published guidelines for safe vegetable fermentation.
Official sources
- National Center for Home Food Preservation: Preparing and Canning Fermented and Pickled Foods.
- USDA Complete Guide to Home Canning: Guide 6 - Preparing and Canning Fermented Foods.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.