Fermentation Problems & Fixes
Most fermentation problems trace to food above the brine, the wrong salt level, or temperature. Keep vegetables submerged with a weight, use the recipe's salt ratio, and ferment somewhere cool and steady. A flat white film (kahm yeast) can be skimmed; fuzzy or coloured mold means discard the batch.
Most fermentation problems come down to food above the brine, the wrong salt level, or temperature. Work through the simple checks, and when in doubt about safety, discard the batch.
Common fermentation problems and fixes
| Symptom | Likely cause | First check | How to fix |
|---|---|---|---|
| White film on the surface | Kahm yeast (usually harmless) | Is it flat and soft, not fuzzy? | Skim it off; keep food submerged and covered |
| Fuzzy or coloured mold | Food exposed to air, contamination | Any fuzz, green, black or pink? | Discard the batch; do not try to salvage it |
| Vegetables float up | No weight or too little brine | Are the vegetables under the brine? | Add a weight and top up brine to submerge them |
| Mushy or soft vegetables | Too little salt or too warm | Salt ratio and room temperature? | Use the recipe’s salt level; ferment somewhere cooler |
| Too salty or too bland | Brine ratio off | Did you weigh salt and water? | Follow a tested brine ratio for the vegetable |
| Little or no bubbling | Cold room or early days | Is it warm enough, and how many days? | Give it time in a warmer spot; activity varies |
Getting a clean ferment every time
Keep vegetables fully under the brine with a weight.
Weigh salt and water to the recipe’s ratio.
Use the airlock or valve so CO2 leaves and air stays out.
Ferment out of direct sun at a steady room temperature.
Frequently asked questions
Is the white film on my ferment dangerous?
A flat, soft white film is usually kahm yeast, which is harmless and can be skimmed off while keeping food submerged. Fuzzy or coloured (green, black, pink) growth is mold, and the batch should be discarded. If it smells putrid rather than sour, throw it out.