How to Get an Open Crumb Sourdough Without Drowning the Dough

Many home bakers chase open crumb by adding more water — and end up with sticky, hard-to-handle dough that produces gummy bread. The truth is open crumb is mostly about gluten development, fermentation timing, and shaping. Hydration is the smallest piece.

What open crumb actually is

Large, irregular holes (1–2 cm wide) distributed throughout the loaf. Glossy interior walls. A light, almost custardy chew.

This is the Tartine-style crumb — and despite reputation, it's achievable at moderate hydration if you nail the other variables.

The three real drivers

1. Gluten development

Open crumb requires very strong gluten. Without it, the bubbles can't grow large without bursting.

Ways to maximize:

• Use bread flour or higher (12%+ protein)
• Long autolyse (1–2 hours)
• Add levain after autolyse
• 4–6 sets of folds during early bulk
• Lamination at the second fold

2. Long, slow bulk fermentation

You need yeast to produce big bubbles, but slowly. Fast bulk = small uniform crumb.

• Aim for 70°F dough temperature, not 78°F
• Bulk for 5–7 hours, not 3–4
• Look for 70–80% rise, not just 30–50%

3. Gentle shaping

Aggressive shaping deflates the bubbles you've built.

• Use a single, light shape
• Skip the pre-shape if your dough is already structured
• Don't degas during transfer to basket
• Use minimal flour on the work surface

Where hydration actually fits

Open crumb requires enough water to make a slack dough — but not so much it can't hold structure.

For most bread flours: 75–80% hydration is the sweet spot. Higher than 82% and you're fighting the dough; lower than 72% and the crumb tightens.

If you want to go higher than 80%, use:

• High-protein bread flour (13%+)
• Long autolyse (2+ hours)
• A small amount of vital wheat gluten (1–2%)

The lamination step

The single biggest open-crumb upgrade: add a lamination step after the first fold.

How:

1. Wet your work surface
2. Tip the dough out
3. Stretch it into a thin sheet, as wide as you can without tearing
4. Fold like a letter (thirds), then fold the ends in
5. Return to the bulk container

This builds extreme extension, which lets large bubbles form during fermentation.

A test recipe

To benchmark your open crumb:

• 500g bread flour (12% protein)
• 380g water (76%)
• 100g active starter (20%)
• 10g salt (2%)

Method:

• Autolyse 1 hour
• Add starter, mix, rest 30 min
• Add salt, mix in
• 4 sets of folds, 30 min apart
• Lamination at second fold
• Bulk 5–7 hours at 72°F (look for 70% rise)
• Pre-shape, bench rest 30 min
• Final shape, cold retard 12 hours
• Bake from cold

This produces an open crumb without drowning the dough.

What to look for in the bulk

Open crumb dough at end of bulk should:

• Have visible large bubbles on the surface and through the side of the container
• Jiggle dramatically when shaken
• Be airy and pillowy when you handle it
• Pass the windowpane test easily

If it's slack and gluey, you've gone too far. If it's tight and bouncy, not far enough.

What to look for in the bake

When you cut into the loaf:

• Holes should be irregular but distributed (not concentrated in one section)
• Walls between holes should be thin and glossy
• The crumb should feel light when you press
• No tunneling under the crust

If you see large holes only in the top half: shaping issue.

If you see uniformly small holes: under-fermented or over-mixed.

When to skip open crumb

Open crumb isn't always desirable. Sandwich bread is better with a tighter crumb. Toast holds spread better with smaller holes. Hosting a dinner party where your guests want stuffing? Tight crumb soaks better.

Open crumb is one style. Master it if you want, but don't think it's the only "good" sourdough.

The patient path

Open crumb is a 6-month skill. Most bakers nail it after 50–80 loaves. The biggest improvement comes from doing slow bulk and gentle shaping, not from adding more water.