1. OSU Extension Catalog
Peer reviewed (Gray level)

Sauerkraut: Problems and solutions

Nellie Oehler
SP 50-745 | Revised January 2025 |
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Common sauerkraut issues and solutions
Problem Cause Prevention
White scum on top
  • Weight on top of cabbage and liquid not sufficient to exclude air during fermentation.
  • Does not occur often; skim off.
  • Follow directions for covering with a plate or plastic bag filled with brine for large batches OR use a silicone pickle pipe, glass weighted disk, or stainless-steel spring with venting lid for small batches.
Slimy kraut (indicates spoilage; discard kraut)
  • Too high temperature during fermentation.
  • Too low salt content.
  • Keep sauerkraut between 70°F and 75°F during fermentation.
  • Use 3T canning salt for 5 pounds of cabbage.
Dark kraut
  • Canning/pickling salt was not used.
  • Cabbage was not trimmed and washed properly.
  • Uneven salting.
  • Too high temperature during fermentation.
  • Too warm storage conditions or stored for long period.
  • Stored in a light location.
  • Use canning or pickling salt.
  • Discard outer leaves and rinse in cool water before shredding.
  • Mix cabbage with salt well and make sure salt is completely dissolved before packing.
  • Keep sauerkraut between 70°F and 75°F during fermenting.
  • Ferment in a dark location.
  • Store canned kraut in a cool, dry, dark location.
Soft kraut (poor quality but safe if it has a clean, acid aroma and taste)
  • Insufficient salt (less than 1.7% concentration).
  • Uneven distribution of salt.
  • Too high temperature during fermentation.
  • Air pockets caused by improper packing.
  • Use the correct amount of salt (3T salt/5 pounds of cabbage).
  • Mix salt well into cabbage before packing.
  • Pack tightly to eliminate air pockets.
  • Ferment in a cool place (70-75°F or lower).
Pink kraut (safe unless slimy)
  • Yeast growth due to excess or uneven salt distribution or improper coverage.
  • Natural pigments in cabbage enhanced by acidity.
  • Use the correct amount of salt, mix well, and keep fermentation temperature between 70°F and 75°F.
  • If caused by cabbage pigmentation, no action needed.
Rotten kraut (discard affected portions)
  • Occurs on the surface if cabbage is not covered sufficiently to exclude air.
  • Cover to exclude air.
  • Discard rotten portions; unaffected portions are safe to consume.
Moldy kraut (small mold patches may be skimmed off, but large amounts require discarding)
  • Usually occurs on the surface in warm fermentation conditions.
  • Not covered tightly.
  • Ferment at temperatures below 75°F and ensure proper coverage.
  • Discard the batch if large amounts of mold are visible.

Source: Adapted from Food Safety Advisor Volunteer Handbook, Washington State University/University of Idaho, 2019

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