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Fix / Sourdough starter

Troubleshooting · New on 9 October 2026

Sourdough starter problems and fixes

No bubbles, no rise, grey liquid on top or bread that is too sour: likely causes, what to change, and when to throw the starter out.

The methodRecord the batch

Most starter problems come down to temperature, flour and feeding rhythm. A young starter is slow by nature: allow 7–10 days before deciding it has failed. 3

No bubbles after several days

Likely causes

  • It is still early: activity often takes 3–5 days to appear and 7–10 days to become reliable 43
  • The jar is too cool 2
  • Only white flour, or irregular feeding 2

What to do

  • Move the jar somewhere at 21–28 °C (70–82 °F) 2
  • Feed with part rye or whole-grain flour 2
  • Feed on a regular schedule and keep going 23

Bubbly but it does not double

Likely causes

  • Cool room or a starter just out of the fridge 25
  • Too long between feeds 3

What to do

  • Give it two or three feeds 12 hours apart at room temperature before baking 5
  • Feed more often, and mark the level to see the rise 36

Grey liquid on top (hooch)

Likely causes

  • Alcohol from the yeast: the starter is hungry and has not been fed for a while 21

What to do

  • Pour it off or stir it back in, then feed 25
  • Feed more often, or keep the starter in the fridge between bakes 3
  • Liquid alone is not a reason to throw the starter out; mould is

Starter or bread too sour

Likely causes

  • A cool starter makes tangier bread 5
  • Using the starter long after its peak

What to do

  • Keep it in the warmer part of the range and bake when it has just doubled 52
  • Change only this one thing for your next loaf and note it in a Batch Card

Mould, coloured spots or a rotten smell

Discard the batch. Do not try to rescue it.

Likely causes

  • Contamination of the starter or jar 1

What to do

  • Throw the starter out, wash the jar thoroughly and start again 13
  • Do not scrape off the mould and keep feeding 2

Change one thing at a time

When a batch disappoints, compare it with the method, change one variable, and note the result in a Batch Card. Two changes at once hide which one helped.

Sources

  1. Colorado State University Extension: Sourdough starter best practicesHooch is a sign of hunger; mould means do not use, clean and restart; do not taste raw starter. Accessed 2026-10-09.
  2. University of Illinois Extension: Sourdough bread 101Feeding at least 1:1:1 starter:flour:water; 21–28 °C (70–82 °F); established in 14 days to a month, usable from day 7; doubles in 4–6 hours; hooch; discard mould; drying is better than freezing for long breaks. Accessed 2026-10-09.
  3. South Dakota State University Extension: Sourdough startersAbout 21 °C (70 °F); active in 7–10 days on average; refrigerate only once established and feed weekly; discard if mouldy, foul-smelling or with green, pink or orange spots. Accessed 2026-10-09.
  4. Washington State University Bread Lab: Sourdough starterEqual volumes of flour and water, fed twice daily; bubbles within 3–5 days; active after about 5 days. Accessed 2026-10-09.
  5. UC ANR Master Food Preservers: Can this sourdough starter be saved?About 22 °C (72 °F); cooler fermentation gives tangier bread; hooch can be stirred in; 2–3 feeds 12 hours apart revive a sluggish starter. Accessed 2026-10-09.
  6. Colorado State University Extension: Caring for your starterAn active starter doubles in 5–8 hours depending on room temperature; refrigerated starter is fed weekly. Accessed 2026-10-09.

Numbers on this page come from these sources. Where sources give a range, we quote the range rather than a single figure.

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