How much salt for sauerkraut

Recipes that say "add 1 tablespoon of salt" are guessing on your behalf, because they can't see how big your cabbage is or which salt you own. The reliable method fermenters actually use is a percentage by weight: you weigh the vegetables, then add salt equal to roughly 2% of that weight. Get this right and the rest of sauerkraut basically takes care of itself.

The 2% rule

For sauerkraut, the target is 2% salt by weight of cabbage (the commonly cited safe range is about 1.5%–2.5%). Salt does three jobs at once here:

• It pulls water out of the cabbage by osmosis, creating the brine the kraut ferments in — no added water needed.
• It favors the right microbes. The lactic-acid bacteria you want tolerate salt; many spoilage organisms don't.
• It keeps texture crisp. Too little salt gives soft, mushy kraut; too much salt stalls fermentation and tastes harsh.

That's why "2%" beats "a tablespoon": it scales perfectly from a single jar to a five-gallon crock, and it doesn't care whether you're using flaky sea salt or dense pickling salt — because you're weighing, not scooping.

The formula

It's one line:

Weigh the trimmed, shredded cabbage after coring — that's the weight that matters. Then multiply by 0.02.

Worked example: one medium cabbage

Say your shredded cabbage weighs 900 grams (about 2 lbs, a typical medium head). At 2%:

• 900 g × 0.02 = 18 grams of salt (roughly 1 level tablespoon of fine salt — but weigh it).

Sprinkle the salt over the cabbage, massage it for a few minutes until it releases liquid and goes limp, then pack it into a jar, pressing until the brine rises above the cabbage. If the cabbage doesn't make quite enough brine to cover after packing, top up with a 2% saltwater solution (20 g salt per 1 liter / 1000 g water). Keep everything under the brine with a weight — exposed cabbage is where mold starts.

The NCHFP benchmark ratio

If you want the tested-recipe anchor behind the 2% rule: the National Center for Home Food Preservation's sauerkraut recipe calls for 25 pounds of cabbage and ¾ cup of canning or pickling salt — that's 3 tablespoons per 5 pounds of cabbage, which works out to roughly 2.25% by weight. So the percentage method and the USDA-lineage recipe land in the same place; the by-weight version just scales cleanly to whatever your cabbage actually weighs and doesn't depend on the density of your salt.

Temperature & how long it takes

Salt is half the equation; temperature is the other half. Per NCHFP:

• 70–75°F (21–24°C): fully fermented in about 3–4 weeks.
• 60–65°F (16–18°C): slower — 5–6 weeks, and many fermenters prefer the flavor of a cool, slow batch.
• Below 60°F: the kraut may simply not ferment.
• Above 75°F: it ferments fast but tends to go soft.

Softness has two usual culprits — too warm, or too little salt — which is why the 2% floor matters. Done kraut is pale, pleasantly sour, and still crunchy; once it tastes right, it keeps tightly covered in the refrigerator for several months, or can be water-bath canned from a tested recipe like the ones in our home canning guides.

Brine percentages for other ferments

"Dry-salting" (salting the vegetable directly, like kraut) works for shredded, juicy vegetables. For whole or chunky vegetables — cucumbers, carrots, beans, peppers — you instead submerge them in a saltwater brine measured as a percentage of the water's weight:

To mix a brine, the math mirrors the kraut rule: a 3% brine is 30 g of salt per 1000 g (1 liter) of water. Weigh the water, multiply by the percentage, stir until dissolved, pour over the vegetables, and weight them down.