Sauerkraut is not done on a schedule. It is done when fermentation has produced the balance of acidity, texture, and flavor you want. That usually takes longer than beginners expect, which is why this question comes up so often.
Most batches people think are “bad” are simply unfinished.
Why “Done” Is the Wrong Mental Model
Sauerkraut does not suddenly flip from unsafe to safe or raw to finished. Fermentation is gradual. The cabbage changes over time, and each stage looks, smells, and tastes different.
Early kraut tastes salty and flat. Mid-ferment kraut smells strong and looks cloudy. Finished kraut tastes sour, clean, and balanced.
If you expect a clear finish line, you will assume something is wrong when nothing is.
What Normal Fermentation Looks Like Over Time
Days 1–3
You should see bubbles forming. The brine often turns cloudy. The smell may be sharp, sour, or sulfurous.
This stage causes the most panic, but it is normal. Early sulfur odors are common as cabbage breaks down and releases natural compounds. If that smell worries you, it is explained in more detail in why sauerkraut can smell sulfurous early on, along with what a healthy ferment normally smells like.
Days 4–10
Bubbling may slow or become irregular. The smell usually softens. The cabbage starts tasting less salty and slightly tangy.
Many people assume fermentation has stopped here. It has not. Gas production naturally rises and falls, and bubbling is not a reliable indicator of activity. This misconception is explained in why a ferment can stop bubbling without being dead.
Weeks 2–4
Acidity increases and the flavor becomes more complex. The cabbage should still be crisp, not mushy.
This is when most sauerkraut reaches a “done” state for everyday eating, though some people prefer a longer ferment.
Taste Is the Signal That Matters Most
Sauerkraut is done when it tastes good to you.
There is no exact day it must be eaten. If it tastes flat or overly salty, it usually just needs more time. If it tastes sharply acidic but clean, it is ready.
If your kraut still lacks sourness and you are unsure why, the most common causes are explained in why sauerkraut sometimes isn’t sour yet.
What “Not Done Yet” Actually Means
Not done does not mean unsafe.
Properly salted and submerged sauerkraut becomes inhospitable to harmful bacteria early in the process. The difference between early and finished kraut is flavor and texture, not safety.
Cloudy brine, strong smells, and uneven bubbling are all normal signs of active fermentation.
What If Something Is Actually Wrong?
A thin white film on the surface is often kahm yeast. It can look alarming, but it is not mold and usually does not mean the batch failed. If you are unsure what you are seeing, how to tell kahm yeast from mold breaks down the difference.
If the kraut tastes overly salty, that is usually a balance issue, not a safety problem. Fixes are explained in how to fix sauerkraut that turned out too salty.
If you are unsure what went wrong overall, start with a breakdown of common sauerkraut problems.
When to Stop Fermenting and Store It
Once the sauerkraut tastes the way you like, move it to the refrigerator. Cold temperatures slow fermentation and preserve texture.
When kept refrigerated and fully submerged, sauerkraut will last for months. Storage options and spoilage signs are covered in how to store finished sauerkraut. (link coming soon)
Final Reality Check
If you used enough salt, kept the cabbage submerged, and gave it time, you did not screw it up.
Fermentation is forgiving. Most failed batches are actually just rushed ones.