Troubleshooting Index: Find the Symptom, Fix It Calmly
Part of: Fermentation School
Something looks wrong. Don’t panic. Find your symptom below and follow the fix.
Quick Diagnosis Table
| Symptom | Likely Cause | Safe to Eat? | Fix |
|---|---|---|---|
| Fuzzy mold on surface | Mold contamination | ❌ No | Discard entire batch |
| Flat white film on surface | Kahm yeast | ✅ Yes | Skim off, continue |
| Cloudy brine | Active fermentation | ✅ Yes | Normal, continue |
| No bubbles after 5 days | Slow fermentation | ✅ Probably | Check temp, wait longer |
| Strong sour smell | Normal fermentation | ✅ Yes | Normal, continue |
| Rotten, putrid smell | Bacterial contamination | ❌ No | Discard |
| Slimy vegetables | Various causes | ⚠️ Maybe | See below |
| Soft, mushy vegetables | Over-fermentation or low salt | ✅ Yes | Eat soon, adjust next time |
| Pink/red brine | Yeast or bacteria | ❌ Usually no | Discard if bright pink |
| Blue/green garlic | Enzyme reaction | ✅ Yes | Normal, safe |
| Bitter taste | Various causes | ⚠️ Maybe | See below |
| Too salty | Over-salting | ✅ Yes | Dilute or rinse |
| Not sour enough | Under-fermented | ✅ Yes | Wait longer |
| White sediment at bottom | Yeast sediment | ✅ Yes | Normal, strain if desired |
Visual Problems
”There’s something growing on the surface”
Fuzzy, raised, colorful (green, black, pink, blue)
- Diagnosis: Mold
- Cause: Vegetables exposed to air, contaminated equipment, or low salt
- Action: Discard the entire batch
- Prevention: Keep vegetables submerged, use clean equipment, proper salt ratio
Flat, white, wrinkly film (like a skin)
- Diagnosis: Kahm yeast
- Cause: Wild yeast from environment, warm temperature, low salt
- Action: Skim off with a clean spoon, push vegetables down, continue fermenting
- Prevention: Use proper salt ratio, keep vegetables submerged, cooler temperature
- Safe? Yes, but can affect flavor if left too long
White particles floating in brine
- Diagnosis: Likely harmless yeast or protein particles
- Action: Strain if bothersome, otherwise ignore
- Safe? Yes
”My brine changed color”
Cloudy, milky, or opaque
- Diagnosis: Active Lactobacillus bacteria
- Action: None needed
- Safe? Yes, this is good
Pink or red tint
- Diagnosis: Possible yeast contamination or pigment from ingredients (beets, red cabbage)
- Action: If bright pink/red and no beets/red cabbage: discard. If from ingredients: normal.
- Safe? Depends on cause
Dark or brown
- Diagnosis: Oxidation or spices (if using dark spices)
- Action: If from oxidation at top: remove top layer. If from spices: normal.
- Safe? Usually yes
Blue or green garlic
- Diagnosis: Enzyme reaction with acids
- Action: None needed
- Safe? Yes, completely normal and safe
Smell Problems
”It smells weird”
Sour, tangy, acidic, pickley
- Diagnosis: Normal fermentation
- Action: None needed
- Safe? Yes
Strong, funky, intense
- Diagnosis: Normal fermentation (especially for longer ferments)
- Action: None needed, but you can ferment less time next batch
- Safe? Yes
Yeasty, beery, bread-like
- Diagnosis: Yeast activity (common in kefir, kombucha)
- Action: Normal for kefir/kombucha. For vegetables: may indicate kahm yeast
- Safe? Yes
Rotten, putrid, like garbage or death
- Diagnosis: Bacterial contamination
- Action: Discard immediately
- Safe? No
Chemical, nail polish, paint thinner
- Diagnosis: Possible contamination
- Action: Discard
- Safe? No
Texture Problems
”My vegetables are slimy”
Slightly slippery on surface
- Possible causes: Kahm yeast, warm temperature, low salt
- Action: Check smell. If good, rinse vegetables and taste. If tastes fine, eat.
- Safe? Usually yes if smell and taste are good
Very slimy, stringy, or rope-like
- Possible causes: Unwanted bacteria
- Action: Discard
- Safe? No
”My vegetables are soft or mushy”
Slightly soft but still hold shape
- Possible causes: Over-fermentation, warm temperature, low salt
- Action: Eat soon, still safe
- Prevention next time: More salt, cooler location, shorter ferment
Completely mushy, falling apart
- Possible causes: Severe over-fermentation or contamination
- Action: If smell is good, can still eat but texture is unpleasant. If smell is off, discard.
- Safe? Depends on smell
”My vegetables are too crunchy”
Very hard, not fermenting
- Possible causes: Too much salt, too cold, not enough time
- Action: Wait longer, move to warmer spot, or accept crunchy texture
- Safe? Yes
Taste Problems
”It tastes too salty”
Causes: Over-salting, used fine salt instead of coarse, didn’t account for water content
Fixes:
- Let it ferment longer — flavors mellow
- Rinse before eating
- Mix with fresh vegetables
- Use as a seasoning in other dishes
Safe? Yes
”It tastes bitter”
Causes:
- Certain vegetables (arugula, some greens)
- Over-fermentation
- Contamination (rare)
Action:
- If vegetables are naturally bitter: normal
- If over-fermented: eat soon
- If bitter + off smell: discard
Safe? Usually yes unless accompanied by other warning signs
”It’s not sour enough”
Causes: Not enough time, too cold, salt too high
Fixes:
- Wait longer
- Move to warmer location
- Check salt ratio (if too high, dilute with fresh vegetables)
Safe? Yes, just under-fermented
”It tastes flat or bland”
Causes: Fermentation stalled, not enough salt, wrong conditions
Action: Check if fermentation is active (bubbles?). If not, may need to restart with proper conditions.
Safe? Yes, but may not be properly preserved
Process Problems
”Nothing is happening (no bubbles)”
After 2-3 days:
- Normal for cool temperatures
- Wait longer
After 5-7 days:
- Check temperature (below 60°F/15°C slows fermentation)
- Check salt (too much salt slows fermentation)
- Taste test — may be fermenting slowly
After 10+ days with no activity:
- Something may be wrong
- Taste test: if sour, it’s working. If not, consider restarting.
”My brine level dropped”
Causes: Vegetables absorbing liquid, evaporation, CO₂ escaping
Fix:
- Press vegetables down to release more liquid
- Add more brine at same concentration
- Ensure proper cover to prevent evaporation
”Vegetables floated above the brine”
Causes: CO₂ lifting them, not enough weight, not packed tightly
Fix:
- Push down immediately
- Add weight
- Check for mold on exposed vegetables
- If mold: discard. If no mold: push under and continue
Kefir-Specific Problems
”My kefir is too sour”
Fix: Ferment for less time, or store in refrigerator sooner
”My kefir is too thin”
Fixes:
- Ferment longer
- Use more grains
- Use creamier milk
”My kefir separated into curds and whey”
Cause: Over-fermentation
Fix:
- Strain immediately
- Use soon or refrigerate
- Next time, ferment for less time
”My kefir grains look weird”
White and cauliflower-like: Normal, healthy Pink or orange: Possible contamination — discard grains and liquid Slimy coating: May be fine — smell and taste test Shriveled and small: May need revitalization — fresh milk, proper temperature
Sourdough-Specific Problems
”My starter isn’t rising”
Causes: Too cold, not enough food, weak yeast
Fixes:
- Move to warmer spot (75-80°F/24-27°C)
- Feed more frequently
- Use whole grain flour for a few feedings
”My starter smells like acetone/nail polish”
Cause: Over-fermented, hungry
Fix: Feed immediately, then maintain regular feeding schedule
”My starter has liquid on top (hooch)”
Cause: Hungry, over-fermented
Fix:
- Pour off or stir in
- Feed immediately
- Feed more frequently
Prevention Checklist
Before you start your next ferment:
- Clean equipment (jars, weights, hands)
- Correct salt ratio (2-3% for vegetables)
- Vegetables fully submerged
- Proper temperature (65-75°F/18-24°C)
- Cover to keep out bugs and dust
- Label with date
When in Doubt
- Look — Fuzzy mold? Discard. Flat film? Skim.
- Smell — Sour = good. Rotten = bad.
- Taste — Pleasant = good. Off = don’t eat.
- Trust your instincts — If it seems wrong, it probably is.
Suggested Next Steps
- Learn more: When to Toss It: Mold vs Yeast vs “Normal” Fermentation
- Learn more: Fermentation Safety Rules
- Recipe: Quick Fermented Vegetables — Start fresh
Most fermentation “problems” are either normal or fixable. When in doubt, trust your senses.
