Sourdough Starter Troubleshooting: 30 Problems Fixed (Complete Guide)

Every problem you might encounter with your sourdough starter, organised into a quick-reference guide. Bookmark this page.

Rising problems

1. Starter won't rise at all

Cause: Too cold, too weak, or not fed recently enough.

Fix: Move to a warmer spot (22-25°C ideal). Feed with a 1:1:1 ratio (starter:flour:water by weight) using wholegrain flour. Give it 6-12 hours. If still nothing, feed again the next day.

2. Starter rises but slowly

Cause: Room too cold, or feeding ratio too aggressive for its current strength.

Fix: Use warm water (25-28°C) to feed. Try a smaller ratio like 1:2:2 to give the culture less to consume. Should double within 4-6 hours at room temperature when active.

3. Starter rises fast then collapses

Cause: Kitchen too warm, or bacterial population outpacing yeasts.

Fix: This is called peaking. Use the starter at its peak (when it has doubled). If it collapses too quickly for you to use it, feed larger amounts (1:5:5) so the food supply lasts longer.

4. Only rises to 50%, never doubles

Cause: Weak yeast population.

Fix: Feed twice a day at room temperature for 5-7 days with 20% wholegrain flour blended into the feed. The wholegrain will boost the wild yeast count.

Appearance problems

5. Layer of dark liquid on top (hooch)

Cause: Starter is hungry — you left it too long between feeds.

Fix: Not a problem. Stir the hooch back in (it adds acidity) or pour off if you want a milder loaf, then feed.

6. Pink, orange or grey patches

Cause: Contamination by unwanted microorganisms.

Fix: Discard entirely. Sanitise the jar with boiling water and start fresh — this is not something to rescue.

7. Fuzzy mould (green, white, black)

Cause: Kitchen too humid, jar not clean, or starter neglected for weeks.

Fix: Discard. Clean the jar with boiling water. Start over. Do not try to scrape off the mould — the spores go deeper than you can see.

8. Watery, thin consistency

Cause: Too much water in the feeds, or old.

Fix: Reduce hydration to a paste (equal weight flour and water). Feed at 1:2:2 ratio.

9. Too thick, dry, cracks on top

Cause: Not enough water, or drying out uncovered.

Fix: Add more water at next feed. Cover with a lid (loose, not sealed) or muslin cloth.

10. Starter has separated into layers

Cause: Long fridge stint. Water separates from flour.

Fix: Normal after cold storage. Stir well before feeding, then feed as normal.

Smell problems

11. Smells like nail polish remover / acetone

Cause: Very hungry starter — excess acetic acid buildup.

Fix: Feed with fresh flour and warm water. Repeat feeds every 12 hours for 2-3 days. Smell returns to yoghurt-like tang.

12. Smells like vinegar

Cause: Slightly under-fed, higher-than-usual acetic acid.

Fix: Feed more frequently (every 8-12 hours) with warmer water to shift the balance towards lactic acid instead.

13. Smells like rotten cheese / bin

Cause: Contamination.

Fix: Discard. Sanitise jar. Start over.

14. Smells sweet, almost fruity

Cause: Very young starter or freshly fed — this is normal.

Fix: No fix needed. As the starter matures the smell will become more complex.

15. No smell at all

Cause: Cold or very slow starter.

Fix: Warm it up, feed with wholegrain flour blend, wait 24 hours. A strong active starter has a distinct smell.

Timing problems

16. Missed a feed by 24 hours

Cause: Life happens.

Fix: Feed as normal. One day is not a problem. Discard down to 50g first if the jar is very full.

17. Missed a feed by 3-7 days at room temperature

Cause: Extended neglect.

Fix: Discard all but 20g. Feed generously (1:5:5) with warm water and half wholegrain flour. May need 2-3 daily feeds to bounce back.

18. Missed a feed by 2 weeks in the fridge

Cause: Normal — fridge starters last a long time.

Fix: Remove from fridge. Let sit for 30 minutes at room temperature. Discard all but 50g. Feed 1:1:1. It will need 2 room-temperature feeds before being bake-ready.

19. Missed a feed by 2 months in the fridge

Cause: Long neglect but often survivable.

Fix: Same as above but expect it to take 5-7 daily feeds before it doubles reliably. Do not give up — most starters can be revived.

Baking with the starter

20. Bread is dense despite active starter

Cause: Under-proofed dough, or starter used too early / too late.

Fix: Use starter at peak (doubled, dome-shaped, before it starts to fall). Extend bulk fermentation to 5-6 hours at 22°C for typical UK kitchen.

21. Bread has huge tunnels, no crumb

Cause: Over-proofed dough or shaping was too gentle.

Fix: Shorter bulk fermentation. Tighter shaping.

22. Bread tastes flat, no tang

Cause: Very warm bulk fermentation favours yeasts over LAB.

Fix: Cold retard in fridge overnight after shaping. This lets the LAB catch up and develop acidity while the yeasts slow down.

23. Bread tastes too sour

Cause: Over-fermented dough or over-fed starter.

Fix: Shorter bulk. Do not retard overnight. Use starter at peak, not past peak.

Advanced problems

24. Starter smells fine but never doubles

Cause: Weak wild yeast population, strong bacterial population.

Fix: Feed with 30% wholegrain rye flour twice a day for a week. Rye is rich in wild yeasts.

25. Starter doubles but bread does not rise

Cause: Under-hydrated dough or salt added too early.

Fix: Check dough hydration (aim 70%+). Add salt after the autolyse, not during initial mix.

26. Refreshed starter smells like alcohol

Cause: Yeast activity dominating over bacterial activity.

Fix: Slow the starter down with a stiffer feed (less water). This favours bacterial acid production.

27. Starter has small bubbles but does not rise

Cause: Gluten network too weak, bubbles escape.

Fix: Switch to strong bread flour instead of plain flour — the higher protein retains gas better.

28. Starter doubles in 2 hours then dies

Cause: Too warm — bacteria consume everything quickly.

Fix: Feed larger ratio (1:5:5 or 1:10:10) so the food lasts longer, or store cooler.

29. Bought a shelf-stable starter that will not activate

Cause: Water too cold, ratio wrong or starter old.

Fix: Use warm water at 32°C. Follow supplier ratio exactly. If our Dough Dough Fast Start Sourdough Starter has not activated in 4 hours, we replace it free.

30. My starter used to work but suddenly does not

Cause: Environmental change (new flour brand, colder kitchen, harder tap water).

Fix: Go back to basics for a week: same flour, room temperature at 22-25°C, twice-daily 1:1:1 feeds. Consider using filtered water if your tap water is heavily chlorinated.

If your problem is not on this list, tell us. If you send a photo and a description we will diagnose it for free and add the solution here for the next baker who hits it.