Master Crumb

My Sourdough Bread Didn't Rise

A flat loaf is the most common sourdough problem. The good news? Once you identify the cause, it's usually easy to fix.

The Top 3 Reasons Bread Doesn't Rise

1. Inactive or Weak Starter

This is the #1 cause of flat bread. If your starter isn't active enough, it can't produce the gas needed to leaven your bread.

Signs your starter wasn't ready:

  • It didn't double within 4-6 hours after feeding
  • It failed the float test (sank in water)
  • It smelled more like flour paste than yeasty/tangy
  • Few or no bubbles visible

The fix:

  • Feed your starter twice daily for 3-5 days to strengthen it
  • Use a warm spot (24-27°C/75-80°F) to encourage activity
  • Try using some whole wheat or rye flour, which ferments faster
  • Only bake when your starter passes the float test

2. Under-Proofing

If you didn't give the dough enough time to ferment, there won't be enough gas production for a good rise.

Signs of under-proofing:

  • Dough hadn't increased much in size during bulk fermentation
  • Dough felt dense, not airy or jiggly
  • Few bubbles visible on surface or sides
  • The bread "burst" in the oven in unexpected places

The fix:

  • Be patient—fermentation can take 4-12 hours depending on temperature
  • Watch the dough, not the clock. Look for 50-75% increase in size
  • Use a warmer spot to speed up fermentation
  • Do the "poke test": dough should spring back slowly when poked

3. Over-Proofing

Paradoxically, too much fermentation also leads to flat bread. The gluten breaks down and can't hold the gas anymore.

Signs of over-proofing:

  • Dough more than doubled and started to deflate
  • Very large bubbles visible, some breaking the surface
  • Dough feels slack and doesn't hold shape
  • Sour, almost alcoholic smell
  • Poke test: dough doesn't spring back at all

The fix:

  • Reduce bulk fermentation time
  • Use a cooler environment or refrigerate sooner
  • Use less starter (10-15% instead of 20%)
  • Watch for the signs of "just right" fermentation

Other Causes to Consider

Temperature Too Cold

Sourdough needs warmth to ferment. In a cold kitchen (below 18°C/65°F), fermentation can take much longer than recipes suggest.

Solutions:

  • Find a warmer spot: top of fridge, oven with light on, near a radiator
  • Use warmer water when mixing (around 30°C/85°F)
  • Extend fermentation time significantly in winter

Not Enough Steam

If your bread rose during proofing but fell flat in the oven, lack of steam might be the culprit. Steam keeps the crust soft so the bread can expand.

Solutions:

  • Use a Dutch oven with the lid on for the first 20 minutes
  • Preheat the Dutch oven for at least 30 minutes at maximum temperature
  • Add ice cubes to a tray at the bottom of the oven (if not using Dutch oven)

Weak Gluten Development

If the gluten network isn't strong enough, it can't trap the gas produced during fermentation.

Signs:

  • Dough never became smooth and elastic
  • Dough tears easily instead of stretching
  • Shape collapsed immediately after shaping

Solutions:

  • Perform more stretch and folds (4-6 sets during bulk fermentation)
  • Use bread flour instead of all-purpose (higher protein)
  • Don't skip the autolyse (30-60 minute rest after mixing)
  • Handle dough gently to preserve structure

Old or Dead Yeast in Starter

If your starter was stored too long without feeding, the yeast may have died off.

Solutions:

  • Feed your refrigerated starter at least once a week
  • If starter hasn't been fed in weeks, it may need several feedings to revive
  • Consider starting fresh if starter shows no activity after a week of regular feeding

How to Diagnose the Problem

Ask yourself these questions:

  1. Was my starter active?
    • Did it double in 4-6 hours after feeding? → If no, strengthen your starter
    • Did it pass the float test? → If no, feed again and wait
  2. Did the dough rise during bulk fermentation?
    • Did it increase by at least 50%? → If no, under-proofed
    • Did it more than double and get slack? → If yes, over-proofed
  3. Did the dough rise during final proof?
    • Did it pass the poke test (slow spring back)? → If no, under-proofed
    • Did it not spring back at all? → Over-proofed
  4. Did the bread rise in the oven at all?
    • If yes but then collapsed → Over-proofed or weak gluten
    • If no rise at all → Under-proofed, cold oven, or no steam

Prevention Checklist

  • ☐ Starter doubles within 4-6 hours after feeding
  • ☐ Starter passes float test before using
  • ☐ Dough ferments in a warm spot (21-27°C/70-80°F)
  • ☐ Bulk fermentation continues until dough increases 50-75%
  • ☐ Dough passes poke test before baking
  • ☐ Dutch oven is preheated screaming hot (at least 30 minutes)
  • ☐ Lid stays on for first 20 minutes of baking

Can I Save My Flat Bread?

A flat loaf is still perfectly edible! Here are some ideas:

  • Slice and toast it—many flat loaves make excellent toast
  • Make croutons or breadcrumbs
  • Use for bread pudding or French toast
  • Make panzanella (bread salad)

Every loaf teaches you something. Take notes on what you did, identify the likely cause, and adjust for next time.