White Film on Sauerkraut: Kahm Yeast vs Mold
A white film on your sauerkraut can be alarming, but it is usually harmless kahm yeast. Learn to identify it and what to do.
Quick Answer
Common Causes
Kahm yeast growth
Kahm yeast is a harmless surface yeast that forms a white, wrinkly film. It thrives when vegetables are exposed to air.
Temperature too warm
Warmer temperatures (above 75°F) encourage kahm yeast growth over beneficial bacteria.
Salt concentration too low
Low salt allows unwanted yeasts to outcompete lactobacillus. Use 2-3% salt by weight.
Actual mold growth
True mold is fuzzy, raised, and often colored (green, black, pink). This is different from flat white kahm yeast.
How to Fix It
Identify the growth
Kahm yeast is flat and wrinkly like a thin skin. Mold is fuzzy and raised. If fuzzy, discard the batch.
Remove kahm yeast
Skim off the white film with a clean spoon. Remove and discard any vegetables that touched it.
Ensure vegetables are submerged
Use a fermentation weight to keep cabbage below the brine. Air exposure causes kahm.
Continue fermenting
After removing kahm, the ferment can continue. Monitor daily and skim as needed.
How to Prevent This
- Keep all vegetables submerged under brine at all times
- Use proper fermentation weights
- Maintain temperature between 65-72°F
- Use 2-3% salt by weight of vegetables
- Use an airlock lid to prevent oxygen exposure
Frequently Asked Questions
Is kahm yeast dangerous?
How do I know if it is mold or kahm yeast?
Should I throw out my sauerkraut if I see white film?
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Disclaimer
This content is for educational purposes only and is not medical advice. Fermented foods affect individuals differently. Consult with a healthcare provider before making significant dietary changes, especially if you have health conditions. Practice proper food safety when fermenting at home.