How to make sauerkraut at home

TL;DR

Weigh trimmed cabbage. Multiply by 0.0225 to get the salt amount in grams. Shred the cabbage, mix in the salt, massage until brine releases (5 to 10 minutes), pack tightly into a jar, weigh down so everything is submerged, cover with an airlock or breathable cloth. Leave at 65 to 72°F for 7 to 21 days, tasting from day 5 onward. When it tastes pleasantly sour and the raw cabbage bite is gone, refrigerate.

The only non-negotiable is the 2 to 2.5 percent salt by weight. Skip the cup measures. Everything else is taste and patience.

Why salt percentage matters

Sauerkraut is a lacto-fermentation: lactobacillus bacteria, present naturally on raw cabbage, convert sugars into lactic acid in an anaerobic environment. The acid drops the pH from neutral to about 3.3 to 3.5, which is acidic enough to inhibit pathogens, mold, and most yeasts. Once the pH drops, the kraut is safe and shelf-stable in the refrigerator for many months.

Salt does three jobs in this process. First, it pulls water out of the cabbage cells (osmosis), producing the brine that the cabbage will ferment in. Second, it suppresses the unwanted microbes (mold, harmful bacteria, surface yeasts) long enough for the lactobacillus to establish dominance. Third, it firms the texture by reinforcing the cabbage’s cell walls.

The right salt percentage by weight gives all three jobs the right balance. Too little salt and the unwanted microbes can outpace the lactobacillus before the pH drops. Too much salt and the lactobacillus itself is suppressed, leading to a stalled ferment that never fully sours. The 2 to 2.5 percent range is the well-established sweet spot.

The conditions

Three variables matter for sauerkraut, in order of importance:

1. Salt: 2 to 2.5 percent of total cabbage weight. Multiply cabbage weight in grams by 0.0225 for a middle-of-the-road target. Less salt for cooler rooms, more for warmer rooms.
2. Temperature: 65 to 72°F is the comfortable range. Below 60°F the ferment slows dramatically (3 weeks or more); above 75°F, surface yeasts and softening become more likely. See fermentation temperature for the broader picture.
3. Submersion: every piece of cabbage stays below the brine line for the entire ferment. Cabbage exposed to air is where mold and kahm yeast establish. A fermentation weight is the simplest fix.

The cabbage variety matters less than the freshness. Firm, dense, recently-harvested green cabbage gives the best result. Old, soft, or rubbery cabbage produces weak brine and mushy kraut.

Step by step

1. Trim and weigh the cabbage

Remove the outer leaves (set 2 or 3 aside for later). Cut the cabbage in quarters and remove the core. Weigh what remains. Write the weight down.

A typical green cabbage trims to 1.2 to 1.8 kg. The exact number does not matter; what matters is that you know it, because the salt amount depends on it.

2. Calculate the salt

Multiply the trimmed weight in grams by 0.0225 for a 2.25 percent target. So a 1.5 kg cabbage (1500 g) gets 1500 × 0.0225 = 33.75 g of salt. Round to 34 g.

For warmer kitchens, target 2.5 percent (multiply by 0.025). For cooler kitchens, 2 percent (multiply by 0.02). Stay within that band; do not improvise lower.

3. Shred the cabbage

Slice the cabbage thin: 2 to 4 mm strips. A sharp chef’s knife is fine. A mandoline is faster and produces more uniform shreds. Avoid food processors; they bruise the cabbage and produce mushy kraut. Pile the shreds in a wide bowl.

4. Salt and massage

Sprinkle the measured salt over the shredded cabbage. Mix with clean hands until the salt is evenly distributed. Then start massaging: squeeze, crush, work the cabbage between your hands. After 2 to 3 minutes of this, water will visibly weep out. Keep going for another 5 to 7 minutes. The volume should reduce by roughly a third, and a generous puddle of brine should pool in the bottom of the bowl.

If the cabbage refuses to release water (an indicator of either an old head or too little salt), let it rest covered for 15 to 30 minutes, then massage again.

5. Pack the jar

Pack the cabbage into the jar in small handfuls, pressing each layer down firmly with a clean fist or a wooden tamper. The goal is to eliminate air pockets and force the brine up over the cabbage. Pack tightly. The jar should fill to no more than two-thirds full; leave space for foaming during active fermentation.

Pour all the brine from the bowl into the jar last. The cabbage should be submerged under the brine line. If it is not yet, push down firmly with the tamper a few more times.

6. Weight and cover

Take one of the reserved outer cabbage leaves, fold it down on top of the shreds, and tuck it around the edges to keep stray pieces under the brine. Place a fermentation weight on top of the leaf. Then cover with an airlock lid or a breathable cloth secured with a rubber band.

Place the jar on a plate or in a shallow bowl. The plate catches brine overflow that will happen during the first week.

7. Wait and taste

Leave the jar at room temperature out of direct sunlight. The first 3 to 5 days are the active phase: bubbling, brine pushing up and over, sometimes a hissing sound if the lid is on. Normal.

Starting around day 5, slip a clean spoon in and taste a strand. The first taste will be salty and sharp. Around day 7 to 10 it shifts: the raw bite fades, a clean sour develops, and the cabbage softens to “still crisp but no longer raw.” That is the window most home krauts get pulled.

If you like a more developed flavor, leave it another week. Up to 21 days produces a more pronounced sour without compromising safety.

What you might see along the way

Brine bubbling out of the jar. Expected in the first week. Place the jar on a plate. The brine level will drop slightly as the cabbage settles; this is fine as long as the cabbage stays submerged.

Cloudy or murky brine. Normal. Healthy ferment brine looks like clouded apple juice rather than clear water. Settling overnight will not clarify it.

A white film on the surface. Likely kahm yeast. Flat, smooth, dull white means harmless. Fuzzy or colored means mold. Stop and check the diagnostic before doing anything else.

Pink or red staining. Most commonly from using iodized table salt or from a piece of red cabbage in the batch. Less commonly, a specific yeast called Rhodotorula. If the texture and smell are otherwise normal, finish the batch but compost it before eating. Use pickling or plain sea salt next time.

Soft or slimy texture. Either too warm a ferment (above 75°F) or too low a salt percentage. Compost and start fresh with a higher salt target (2.5 to 3 percent) and a cooler spot.

A strong sulfurous smell early on. Some cabbage produces faint sulfur compounds in the first 3 to 5 days. They dissipate as fermentation proceeds. If the smell persists past day 7 or smells putrid rather than sulfurous, discard.

Common mistakes

Using volume measurements for salt. The single biggest cause of failed batches. Different salts have wildly different densities; cup measurements give wildly different actual salt amounts. A scale solves this permanently.

Skipping the massage. Without proper massage, the cabbage does not release enough water to make its own brine. The result is a jar of partially-submerged cabbage that surface-molds within a week. Spend the 10 minutes.

Packing loosely. Loose packing leaves air pockets, and air pockets are where surface microbes establish. Pack hard. The cabbage should sit dense and uniform in the jar, with no visible voids.

Sealing the jar tight during fermentation. CO2 pressure builds and either pushes brine out around the seal or, in extreme cases, cracks the jar. Use a breathable cover, an airlock lid, or a loose-fit lid that lets pressure escape.

Tasting too early and deciding it failed. Day 3 sauerkraut tastes harsh, salty, and unpleasant. That is not the final flavor. Wait until day 7 minimum before judging.

Troubleshooting

The brine never covers the cabbage. Cabbage was probably old, the massage was insufficient, or the salt was uneven. Add a 2 percent topping brine (20 g salt per 1000 g water) until everything is submerged. Continue the ferment normally.

The fermentation never starts. No bubbling, no smell change after a week. Almost always a temperature issue. The kitchen is too cold. Move the jar to a warmer spot (top of the refrigerator works) and give it another 5 to 7 days. If still inactive, the salt percentage may have been too high; check the math.

The kraut tastes too salty even after 2 weeks. The salt percentage was set too high. The flavor mellows in the refrigerator over a few weeks. If unacceptable, use the kraut in cooked applications where its salt contributes to the overall seasoning.

The kraut went mushy. Most commonly: temperature too warm (above 75°F), or salt too low (under 1.5 percent), or shredded too thin and over-massaged. Next batch, target 2.5 percent salt, find a cooler spot, and massage just until brine releases rather than into pulp.

A specific patch of kraut is discolored or slimy near the surface. Skim that section off and continue. If the discoloration extends deep into the body of the ferment, discard.

For variations on the standard kraut (sauerruben with turnip, curtido with cabbage and carrot, kraut with caraway or juniper), see the variations in vegetable ferments. For the underlying salt-percentage math used across every vegetable ferment on this site, see the fundamentals.