How to Ferment Cabbage Into Sauerkraut

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Learning how to ferment cabbage is the way to turn a garden crop into sauerkraut without canning. Fermentation depends on salt, time and temperature working together: the salt draws juice out of the shredded cabbage and keeps spoilage organisms in check while the natural bacteria produce acid. Extension sources describe a dry-salt method with specific salt amounts, and they warn that a wrong salt level can spoil the batch. This guide explains those steps and marks what the sources leave open.

Quick answer

• Weigh the cabbage and use salt at about 2 to 2.5 percent of the cabbage weight, following the UC publication’s stated range.
• Keep the shredded cabbage submerged under its own juice while it ferments, using a weight and a cover.
• Ferment at 70 to 75 degrees Fahrenheit, as the WSU directions advise. The process is usually complete in about 3 to 4 weeks.
• Use pickling or canning salt. Iodine and anti-caking additives can interfere with fermentation.

Why salt is the key ingredient

Sauerkraut is a salt-cured ferment, not a vinegar pickle. The UC Cooperative Extension publication explains that “When salt is added to shredded cabbage, it causes juice to be extracted from the cabbage,” and that this juice carries the sugars the bacteria need. The salt also keeps the environment favorable for the right bacteria. The WSU directions put it this way: “The salt encourages the sugar in the cabbage to be changed to lactic acid, producing sauerkraut.”

The salt amount is not a matter of taste. The WSU directions warn that “A higher or lower concentration of salt results in an inferior product and spoilage may occur.” That is why the UC publication gives a weight-based ratio rather than a volume measure. It states that “the ratio of salt to cabbage is 2.25 to 2.50 percent salt by weight.” Weighing the cabbage and salt avoids guesswork that a volume measure invites.

Choosing and preparing the cabbage

Use fresh, firm heads, and trim away any damaged outer leaves. The UC publication directs cooks to “Cut heads into halves or quarters and core,” then to “Slice or shred the cabbage to about the thickness of a quarter.” Consistent shreds help the salt penetrate evenly and make the cabbage easier to pack into the crock or jar. Weigh the prepared cabbage before you add salt, since the salt amount depends on that weight.

The WSU directions describe the dry-salt method, in which salt draws juice from the cabbage to form a concentrated brine. Combine the salt with the shreds, then pack the mixture firmly into a clean, food-safe container until juice covers the cabbage.

Packing, weighting and covering

Once the cabbage is packed, it has to stay under its brine. The WSU directions state that “Shredded cabbage must be kept submerged in brine while fermenting.” The UC publication recommends a practical way to do this: “a brine-filled plastic bag is one of the easiest ways to both cover and weight down the cabbage.” The bag holds the cabbage under the juice and keeps air out.

The UC publication adds that you should “Weight down the cabbage so it remains under the juice and cover the fermenting vessel.” A jar filled with water is a common weight, as the same publication notes. Check the container regularly during fermentation to confirm that the cabbage is still submerged. Keeping the cabbage under the brine is the step the WSU directions treat as required.

Keep the container in a spot that stays in the range the sources recommend. The WSU directions say to “Store at 70o to 75o F to ferment.” Warmer rooms ferment faster, and cooler rooms slow the process. Plan for about three to four weeks, and taste the kraut as it develops.

Checking the batch as it ferments

The WSU directions state that the “fermentation is completed in about 3 -4 weeks,” so use that as the planning window rather than a fixed deadline. Check that the cabbage stays under the brine throughout the process.

Salt level is the main variable to get right. The WSU directions say that if the salt is wrong, the result is “an inferior product and spoilage may occur.” If a batch shows signs of spoilage, the sources do not describe a way to rescue it, so do not treat a spoiled batch as safe to eat.

Storing finished sauerkraut

The sources in this article focus on the fermenting process itself. They do not give a tested storage method or storage time for finished sauerkraut, so check a current extension storage guide before deciding how to store it. Do not process fermented sauerkraut in a canner unless a tested recipe for that exact product tells you to.

For related reading on salt-based preservation and garden harvest, see our guide on how to pickle green beans, which uses a brine rather than fermentation. For storing other fresh produce from the garden, see how to store freshly harvested vegetables.

How we chose

We used three non-retail sources: the WSU Extension sauerkraut-making directions, the UC Cooperative Extension sauerkraut publication, and a second UC Cooperative Extension sauerkraut PDF that gives the salt measures in volume and a weight-based instruction. Each was opened on 2026-10-27, and the quotes above were copied from the fetched text. We left out recipe blogs, fermentation kits and retail pages, because those sources make salt and time claims that did not appear in the extension text we retrieved.

What we could not verify

The sources do not agree on one exact salt number. The UC publication gives 2.25 to 2.50 percent by weight, while the WSU directions give a volume measure of 1 1/2 tablespoons of salt per quart of water for the brine and describe the dry-salt method without a single percentage. The second UC PDF gives “Add 3 tablespoons of salt” in one step, but the batch size for that step is not clear from the retrieved text. We could not reconcile those figures into one number for every batch size.

What the sources do not say

The sources do not give a tested storage life for finished sauerkraut, and they do not say how long a jar keeps once opened. They do not specify a single fermenting temperature for every kitchen, and they do not give pH targets. Anyone fermenting at a different temperature or with a different cabbage variety should watch the batch closely and rely on the signs described above.

Frequently asked questions

How much salt do I use to ferment cabbage?

The UC publication gives 2.25 to 2.50 percent salt by weight of the cabbage. The WSU directions use a volume measure for the brine, so weigh the cabbage and salt where possible, since salt crystal size changes how much a spoon holds.

What temperature should sauerkraut ferment at?

The WSU directions say to “Store at 70o to 75o F to ferment.” Warmer temperatures ferment faster, and cooler temperatures take longer.

Why does my sauerkraut need to stay under the brine?

The WSU directions state that “Shredded cabbage must be kept submerged in brine while fermenting.” Exposed cabbage is more likely to spoil, so use a weight and a cover to keep it under the juice.

How long does sauerkraut take to ferment?

The WSU directions state that fermentation is “completed in about 3 -4 weeks.” Taste the batch as it develops, and treat that window as a planning estimate rather than a fixed rule.

Can I use table salt to make sauerkraut?

The UC publication advises using a salt made for canning or pickling, and it warns about iodine and other additives in table salt. Use pickling or canning salt for the most consistent result.

Sources

• Washington State University Extension, sauerkraut-making directions: https://wpcdn.web.wsu.edu/wp-extension/uploads/sites/2057/2021/04/Sauerkraut-Making-directions.pdf (opened 2026-10-27)
• UC Cooperative Extension, sauerkraut publication: https://class.ucanr.edu/sites/default/files/2020-03/321721.pdf (opened 2026-10-27)
• UC Cooperative Extension (PDF hosted at ccfruitandnuts.ucanr.edu), sauerkraut publication with volume-based salt measures: https://ccfruitandnuts.ucanr.edu/sites/default/files/2020-11/339529.pdf (opened 2026-10-27)