Fermentation Brine Calculator
Get the exact salt weight for a safe brine, by brine-only or total-weight method, for pickles, olives, kraut, and kimchi.
Never go below 2% for vegetable ferments. Use non-iodized salt (pickling, kosher, or sea salt without anti-caking additives), and use filtered or boiled-and-cooled water if your tap water is heavily chlorinated, since chlorine can slow fermentation. A scale beats teaspoons; the tsp figure is a rough backup only.
How it works
Pick the method that matches what you're making, enter a weight, and choose a brine strength. The brine-only method treats salt as a percent of the water alone, which is right for pickles, olives, and feta sitting in a jar of liquid brine. The total-weight method treats salt as a percent of the vegetable and water added together, which is the convention for shredded kraut and kimchi, where there's no separate pool of brine until the salt draws water out of the cabbage itself.
Worked example: 1000 g of water, brine-only method, 2% strength. The calculator multiplies 1000 by 0.02 to get 20 g of salt, then divides that by 5.9 g per teaspoon for a rough 3.4 tsp. Switch to the total-weight method with the same 1000 g (say, 700 g cabbage plus 300 g water) and it still lands on 20 g of salt, since 2% of 1000 is 20 either way. The method only matters for what you're weighing, not the math itself.
FAQ
Why does the site default to 2%?
2% is the floor for safe, reliable vegetable lacto-fermentation. Enough salt below that and you risk mold, yeast, and spoilage organisms outcompeting the lactic acid bacteria you want. Go up to 3.5% for olives, which need extra salt to leach out their natural bitterness, or 5% for pickles you want to store for months rather than weeks.
Do I have to use a scale?
A scale gives you the accurate number, and it's worth the ten dollars if you ferment regularly. The teaspoon figure is a rough stand-in for when you don't have one, but fine sea salt, kosher salt, and pickling salt all pack differently by volume, so the weight in grams is always the number to trust.
What salt should I use?
Non-iodized salt without anti-caking agents: pickling salt, canning salt, kosher salt, or a plain sea salt. Iodine and anti-caking additives can cloud a brine or interfere with fermentation, and some table salts add both.
Does the water matter?
Yes. Heavily chlorinated tap water can slow or stall fermentation because chlorine is designed to kill bacteria, including the ones you want. Filtered water, or tap water left out for 24 hours (or boiled and cooled) to let the chlorine dissipate, is a safer bet.
For more on brine strength and salt choice, see how to make a salt brine for fermenting vegetables, why salt matters in fermentation, and what salt you should use for fermenting.