How to Ferment Sauerkraut in a Canning Jar Without Special Equipment

Sauerkraut has a reputation for needing a crock, a cellar, and a patient grandmother. A quart canning jar, a head of cabbage, and salt will get you there. The method below makes a small batch you can eat within a week, with no airlock, no starter culture, and no special tools. If you can make coleslaw, you can make kraut.

Why a plain jar works

Fermentation is not complicated: salt pulls water from shredded cabbage, creating brine. That brine keeps oxygen away and lets lactic acid bacteria do their work. Those bacteria turn sugars into acid, which preserves the cabbage and gives sauerkraut its tang. A jar is simply a container that holds the cabbage under the brine. An airlock is nice, but it is not required. Your job is to keep the cabbage submerged, keep the jar clean, and let time pass.

Small batches ferment faster than a big crock because they warm up to room temperature quickly. A quart jar is enough for one or two people. A half-gallon jar gives you more kraut with the same effort.

What you need

One medium green cabbage, about 2 to 3 pounds
Fine sea salt or pickling salt. Avoid iodized table salt if you can; its anti-caking agents can make brine cloudy. Aim for about 2 percent salt by weight: 20 grams per 1 kilogram of shredded cabbage. Without a scale, use 1½ to 2 tablespoons per 2 pounds of cabbage.
A clean quart or half-gallon canning jar
A large bowl
A knife and cutting board, or a mandoline
Something to press: a wooden spoon, potato masher, or clean hands
A weight: a small zip-top bag filled with brine, a clean glass weight, or a folded outer cabbage leaf
A loose lid, plastic storage cap, or clean cloth and rubber band

Shred, salt, and massage

Remove the outer leaves and set one aside if it is clean and flexible. Cut the cabbage into quarters, slice out the core, and shred the rest as thinly as you can. A mandoline makes quick work of it, but a sharp knife is fine. You want pieces about the thickness of a coin or thinner.

Put the shredded cabbage in the large bowl and sprinkle the salt over it. Toss with clean hands. Now massage. Squeeze handfuls, turn the pile, and repeat. After five to ten minutes, the cabbage will look glossy and a pool of brine will form at the bottom. Let it sit for fifteen minutes if you need a break. The salt is doing the work; you are just helping it along.

Pack the jar and keep it under brine

Pack a handful of cabbage into the jar. Press down firmly with your fist, a spoon, or a tamper. Add more cabbage and press again. Keep packing until the jar is about three-quarters full and the cabbage is below the shoulder of the jar.
Pour any brine from the bowl over the cabbage. The liquid should cover the cabbage by at least half an inch. If it does not, mix 1 teaspoon of salt with 1 cup of water and add just enough to cover.
Fold the reserved outer leaf and tuck it over the top of the cabbage. This helps hold small shreds down.
Add your weight. If you use a zip-top bag, fill it with brine, not plain water, so a leak will not dilute the ferment. Seal it and press it gently onto the cabbage.
Leave at least 1 inch of headspace. Cover the jar with a loose lid or a cloth secured with a rubber band. If you use a tight lid, burp the jar once a day to release gas.

Ferment, taste, and fix problems

Put the jar in a cool, dark spot, ideally between 65°F and 72°F. You should see bubbles within two or three days. The brine may look cloudy, and the smell will turn from raw cabbage to sour. That is normal.

Start tasting after five days. Use a clean fork to pull out a strand. When it tastes pleasantly sour and the texture is tender but still crunchy, it is ready. Most jars finish in one to three weeks. Cooler rooms slow it down; warmer rooms speed it up.

Check the jar every day or two. Press the cabbage back under the brine if it floats. Skim off any white film, which is usually harmless kahm yeast. If you see fuzzy mold in green, blue, black, or pink, discard the batch. Do not try to scrape it off. If the kraut is soft and slippery, it likely got too warm or had too little salt. If it is too salty, drain and rinse a portion before eating.