Reviews
Part of Kimchi as the third vegetable ferment: short, then refrigerated
Storage faults in a vegetable ferment: soft, dark and slimy kraut
Soft, dark or slimy kraut traced to its cause: how temperature, salt, trimming and brine level explain a vegetable ferment fault, and which ones mean discard.
What to take away
- Sharper is aging, not a fault. Soft, dark and slimy are faults, and each one traces back to a short list of causes.
- Soft and dark kraut both point back to temperature70 to 75 F during fermentation, and a cool, dry, dark place for canned jars.
- Dark kraut also points at trimming, salt type, uneven salt, and storage that was too warm or too long.
- Slimy kraut is spoilage. Discard it rather than trying to rinse or cook it out.
Aging or a fault?
Decide first whether the jar is merely older. Cold slows the bacteria that made the food and does not remove them, so a refrigerated jar keeps souring. A jar at four weeks and the same jar at four months are different products, and most people prefer the younger one.
How a refrigerated ferment changes
- 4 weekssharp, young-tasting kraut
- 4 monthssame jar, different product
- 4-6 monthspickles in original container
- Regularlyremove surface scum and molds
Sourness that sharpens over weeks is the ferment doing what it does. Fully fermented pickles kept in their original container keep about four to six months refrigerated, provided surface scum and molds are removed regularly. Canning them is the more reliable way to store them.
Sliminess, softening or a bad odor are different. White sediment at the bottom of a live jar is not a problem on its own. For what freezing does to texture, see fridge and freezer storage.
Soft and dark kraut
Oregon State University Extension's list of sauerkraut problems and solutions traces the common faults to a small set of causes. Soft kraut and dark kraut both point back to temperature. Keep sauerkraut between 70 and 75 F during fermentation, and store canned kraut in a cool, dry, dark location.
Faults and their causes
- Soft krauttemperature too warm
- Dark krautwarm, long, or poor trimming
- Dark krautwrong salt or uneven salt
- Slimy krautspoilage, discard it
- Keep fermenting kraut at 70-75 F
- Store canned kraut cool, dry, dark
Dark kraut has more causes than warmth. It also follows from cabbage that was not trimmed and washed properly, from salt that was not canning or pickling salt, from uneven salt distribution, and from storage that was too warm or too long.
Slimy kraut
Slimy kraut indicates spoilage and should be discarded. Do not rinse it, cook it, or try to rescue the batch. The fault is not a flavor problem that a recipe can mask, and the other signs, softening and a bad odor, point the same way.
The wider causes of a failed batch are set out in what goes wrong and why. Write the start date and the fermentation range on the lid, so a soft or dark jar can be traced to a warm week rather than guessed at.
Fault guide
Match what you see to the likely cause, then change one thing at a time. A jar with two faults may have two causes, so check temperature first, then trimming and salt, then whether the vegetables stayed under the brine.
| What you see | Likely cause | What to do |
|---|---|---|
| Sharper, more sour jar | Age in the refrigerator | Eat it sooner next time |
| Soft kraut | Temperature outside 70 to 75 F | Hold the next batch in range |
| Dark kraut | Warm storage, untrimmed cabbage, wrong or uneven salt | Store jars cool, dry and dark |
| Surface scum or mold | Vegetables not held under brine | Remove it regularly |
| Slimy, soft or bad smelling | Spoilage | Discard |
| White sediment, nothing else | Normal in a live jar | Leave it |
Keeping the vegetables under the brine
A dry shoulder is where surface growth starts, so the weight matters. If it does not exclude air, use a plate or a brine-filled bag for large batches, and for small ones a silicone pipe, glass weighted disk, or stainless spring with a venting lid.
Skim surface growth as soon as you see it. Top up with boiled and cooled brine at the recipe's concentration rather than plain water, which dilutes what protects the jar.
A vinegar pickle fails on a different clock
Not everything in the refrigerator is a ferment. University of Maine Extension's refrigerator spring pickles pack raw vegetables into pint jars and cover them with boiled brine made from 5 percent acidity vinegar.
Fill to within 1/2 inch of the rim and refrigerate. Flavor develops in one to two days, and the jars are used within two weeks.
That is two weeks, not two months, because a vinegar pickle that never fermented has no acid production keeping it. Judge such a jar by its date, and check the other vegetable ferment ideas for the ones that do ferment.
Common questions
Can I top up a jar with water?
No. Use boiled and cooled brine at the recipe's salt concentration. Water lowers the salt level in the jar.
Why did my canned kraut go dark?
Usually warm storage, or salt that was unevenly mixed or not canning salt. Store canned jars cool, dry, and dark.
Is white sediment at the bottom a problem?
Not on its own in a live jar. Sliminess, softening, or a bad odor are the signs that mean discard.
