Quick Diagnosis
What is the starter doing (or not doing)?
🛒 Recommended Products
We recommend the following tools for this recipe:
Digital Kitchen Scale
Essential for consistent feeds and measuring detritus
Glass Jar for Starter
Clear jar lets you see rises and activity
Jar Spatula
Helps scrape starter cleanly and measure discard
Clear Straight-Sided Container
Useful for building larger levains and observing growth
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Causes & Solutions
Starter starved or underfed
very commonSymptoms:
- • No visible rise after a feed
- • Few or no bubbles
- • Thin, sluggish texture
Why does this happen?
Yeasts and lactic acid bacteria need fresh food and water to grow. A starter kept too long between feeds exhausts available sugars and becomes inactive.[1][2]
🚨 Immediate Fix:
Discard most of the starter, keep 20–50 g, then feed at a ratio of 1:2:2 (starter:flour:water) every 12 hours at room temperature. Use a digital kitchen scale for accuracy.
📅 Long-term Fix:
If kept at room temperature: feed daily. If refrigerated: feed weekly and before baking. Keep a feeding log to learn your starter's rhythm.[1]
🧪 Test:
After 2–3 consecutive regular feeds at warm room temperature (24–26°C) the starter should show consistent doubling and pronounced bubbles.
Microbial imbalance — too acidic or acetone smell
commonSymptoms:
- • Sharp vinegar or acetone smell
- • Darkened color or watery separation
- • Bubbles present but weak
Why does this happen?
When lactic acid bacteria outcompete yeasts (or when yeasts are suppressed), the starter becomes overly acidic. Acetone smell indicates starvation and buildup of acidic metabolites.[2][1]
🚨 Immediate Fix:
Refresh with multiple consecutive feeds using a stiffer ratio (1:3:3) and discard the hooch. Switch to milder flour (white bread flour) for several feeds to favor yeasts. Use a glass jar for starter so you can track rise.
📅 Long-term Fix:
Maintain regular feeds, avoid very long intervals at warm temperatures, and keep hydration consistent. If problem recurs, build a new starter from a healthy culture following controlled feedings.[1][2]
🧪 Test:
A rescued starter will reduce acidity smell and regain a balanced, yeasty aroma after 24–72 hours of regular feeds.
Temperature too low or inconsistent
commonSymptoms:
- • Very slow doubling (>12 hours)
- • Bubbles only after long periods
- • Good aroma but sluggish activity
Why does this happen?
Microbial activity is temperature-dependent. Cooler temperatures slow fermentation and extend doubling time; warmer temperatures speed it up.[1][2]
🚨 Immediate Fix:
Move the starter to a warmer spot (24–26°C). Use a warm-proof environment like an oven with just the light on or a clear straight-sided container placed near a warm appliance. Keep feeds regular.
📅 Long-term Fix:
Learn your kitchen's seasonal temperature profile and adjust feed frequency or water temperature accordingly. For predictable results, use a small proofing box for feeds.[1]
🧪 Test:
Measure times: at ~25°C a healthy starter should show clear rise within 4–8 hours after feeding; adjust expectations for cooler kitchens.
Starter neglected in fridge — hooch and separation
mediumSymptoms:
- • Dark liquid on top (hooch)
- • Starter appears separated or thin
- • Weak activity after a single feed
Why does this happen?
In refrigeration, activity slows but continues; alcohol (hooch) and acids build up. A single feed may not be enough to revive cells that have been dormant for weeks.[2]
🚨 Immediate Fix:
Pour off hooch, discard most starter leaving 20–50 g, and perform 2–3 daily feeds at room temperature using a jar spatula to scrape and mix. Prefer white or bread flour for initial rebuilds.
📅 Long-term Fix:
If you don't bake weekly, keep starter in the fridge but refresh it 24–48 hours before baking with at least two feeds at room temperature. Label next feed times to avoid long neglect.
🧪 Test:
After 48–72 hours of regular warm feeds the starter should regain volume and bubbling; if not, consider rebuilding a fresh starter.
Flour quality or water issues
rareSymptoms:
- • Starter remains sluggish despite correct feeding
- • Unusual odors after feeds
- • No rise even after multiple feeds
Why does this happen?
Old or rancid flour lacks fermentable sugars and enzymes; chlorinated water can inhibit microbes. Flour types also supply different nutrient profiles for yeasts and bacteria.[1][2]
🚨 Immediate Fix:
Switch to fresh, high-protein bread flour or a blend of whole-grain and white flour for a few feeds. Use filtered or dechlorinated water.
📅 Long-term Fix:
Store flour cool and sealed. Rotate flour stock. If your tap water is chlorinated, let it sit overnight or use filtered water for starter feeds.
🧪 Test:
If switching flour and water restores activity within 1–3 feeds, the issue was likely ingredient-related.
Contamination (molds or odd colors)
rareSymptoms:
- • Pink, green or fuzzy mold
- • Unpleasant rotten smell (not vinegar/acetone)
- • Persistent discoloration
Why does this happen?
Mold or harmful bacteria can contaminate a starter when hygiene lapses or the starter is left too long without feeding. These are signs the culture is unsafe to keep.[2]
🚨 Immediate Fix:
Discard the starter and all contaminated tools. Start a new culture. Do not attempt to rescue a visibly moldy starter.
📅 Long-term Fix:
Keep jars and utensils clean, use fresh hands or dedicated tools, and maintain a consistent feeding schedule to prevent contamination.
🧪 Test:
Visible mold or off-putting rotten smells are a definitive fail—do not use the starter.
🆘 How to Rescue an Inactive Starter — step-by-step
Starter hasn't risen for days but no mold
Solution: Discard all but 20–50 g, then feed 1:3:3 (starter:flour:water) twice daily at 24–26°C for 48–72 hours using a [digital kitchen scale](https://amzn.to/4pUMVHi). Use strong bread flour to favor yeast growth.[1]
Success chance: high with regular feeds
Starter in fridge with hooch and weak activity
Solution: Remove hooch, refresh with larger feeds (1:4:4) over 2–3 days at room temperature. If recovery stalls, switch to part-wholegrain flour to boost nutrients.[2]
Success chance: good
Starter smells rotten or shows colored mold
Solution: Discard starter and clean the jar. Begin a new starter following controlled, clean steps.
Success chance: required (must restart)
Prevention
- ☐ Feed with accurate ratios using a digital kitchen scale
- ☐ Use a glass jar for starter so you can observe rise and separation
- ☐ Keep starter at stable temperature for predictable activity (24–26°C for active feeding)
- ☐ If refrigerating, refresh starter 24–48 hours before baking with at least two feeds
- ☐ Use filtered water and fresh flour; store flour cool and sealed
- ☐ Maintain clean tools — a jar spatula helps reduce contamination