How Professional Bakers Get an Open, Airy Sourdough Crumb

An open, airy sourdough crumb is one of the hallmarks of a well-made artisan loaf. Those irregular holes, light texture, and delicate structure are not simply the result of adding more water to the dough. They are the result of several factors working together: fermentation, hydration, gluten development, shaping, scoring, steam, and baking.

Professional bakers don't rely on a single trick to create an open crumb. Instead, they carefully control the entire process, from mixing the dough to the moment the loaf comes out of the oven.

The good news is that many of these techniques can be reproduced at home. With the right flour, fermentation, handling, and a well-preheated cast iron bread oven, you can produce sourdough bread with a beautifully open and airy crumb in your own kitchen.

1. Start with the Right Flour

The foundation of an open sourdough crumb is strong gluten development.

Gluten forms the structure that allows the dough to stretch and hold the carbon dioxide produced by fermentation. If the gluten network is too weak, the gas escapes and the loaf becomes dense.

Strong bread flour is generally a good starting point because it contains enough protein to develop a strong gluten network.

However, higher protein does not automatically mean better bread. Flour quality, protein quality, hydration, fermentation, and mixing all affect the final result.

How to improve it:
Use a strong bread flour or a flour specifically suited to sourdough baking. If you are adding whole wheat or rye flour, remember that these flours can change the dough structure and often produce a denser crumb.

2. Get Your Hydration Right

Hydration refers to the amount of water relative to the amount of flour in the dough.

Higher hydration generally produces a dough that can develop a more open crumb, but adding more water isn't a shortcut to better sourdough.

A dough that is too wet for the flour you are using can become difficult to handle and may not develop enough structure to hold its shape.

How to improve it:
Start with a hydration level your flour can handle. Once you are comfortable handling the dough, gradually increase hydration if you want a more open crumb.

For many home bakers, something around 70–80% hydration is a useful range to explore, although the ideal level depends heavily on the flour.

3. Don't Underestimate Autolyse

Autolyse is a period of rest after mixing flour and water, usually before adding the remaining ingredients.

During this rest, the flour absorbs water and enzymes begin modifying the dough. This can make the dough more extensible and easier to develop.

A good autolyse can be particularly useful when working with high-hydration sourdough dough.

How to improve it:
Mix the flour and water until no dry flour remains and allow the mixture to rest before adding the sourdough starter and salt.

The exact duration can vary from around 20 minutes to several hours depending on the recipe and flour.

4. Build Gluten Without Overworking the Dough

An open crumb requires a strong but extensible gluten network.

Professional bakers develop gluten through a combination of mixing, resting, stretching, and folding rather than simply kneading the dough aggressively.

Stretch-and-fold and coil-fold techniques allow you to strengthen the dough while preserving its extensibility.

How to improve it:
During bulk fermentation, perform several rounds of stretch and folds at appropriate intervals. As the dough becomes stronger, you can reduce the frequency of handling.

The goal is a dough that feels elastic and holds its shape without becoming excessively tight.

5. Use an Active Sourdough Starter

Your starter is the engine of sourdough fermentation.

A weak or inactive starter may take much longer to ferment the dough and can produce poor gas production.

An active starter should show clear signs of fermentation, such as rising significantly after feeding, bubbles throughout the mixture, and a pleasant fermented aroma.

How to improve it:
Use your sourdough starter when it is active and near its peak rather than immediately after feeding.

A predictable starter makes fermentation much easier to control.

6. Fermentation Is More Important Than the Clock

One of the biggest differences between professional and beginner sourdough baking is how fermentation is judged.

Recipes often give a specific number of hours for bulk fermentation, but dough doesn't ferment according to a clock.

Temperature, starter strength, flour, hydration, and dough quantity all affect fermentation speed.

How to improve it:
Learn to read the dough instead of relying exclusively on time.

During bulk fermentation, look for signs such as:

• Increased volume

• Bubbles along the sides of the container

• A smoother, more elastic appearance

• A slightly domed surface

• A lighter, aerated texture

• The dough becoming more difficult to stretch without tearing

These signs are more useful than simply waiting for a specific number of hours.

7. Don't Under-Ferment the Dough

Under-fermented sourdough is one of the most common causes of a dense crumb.

If the dough has not produced enough gas or developed enough structure, there simply isn't enough internal pressure to create a light, airy loaf.

An under-fermented loaf may feel dense, have a tight crumb, and show relatively small and uniform holes.

How to improve it:
Give the dough enough time to complete bulk fermentation. If your kitchen is cold, fermentation may take considerably longer than the recipe suggests.

8. Don't Over-Ferment the Dough

The opposite problem is over-fermentation.

Once fermentation progresses too far, the gluten structure can begin to weaken. The dough may become very slack, sticky, difficult to shape, and unable to hold gas effectively.

The result can be a flat loaf with a dense or gummy crumb despite having a high hydration.

How to improve it:
Learn to recognize when bulk fermentation is complete. The dough should be aerated and lively but still have enough strength to hold its shape.

9. Handle the Dough Gently

Once your dough has developed a good gluten network and accumulated gas during bulk fermentation, excessive handling can knock out some of that gas.

This doesn't mean you should never touch the dough.

It means that handling should become increasingly gentle as fermentation progresses.

How to improve it:
Use confident but gentle movements when dividing, pre-shaping, and shaping your sourdough dough.

Avoid repeatedly pressing or kneading the dough during final shaping.

10. Pre-Shape Before Final Shaping

Pre-shaping gives the dough an opportunity to organize its gluten structure before the final shaping.

It can also make a high-hydration dough considerably easier to handle.

How to improve it:
Gently form the dough into a loose round and allow it to rest before final shaping.

The rest period allows the gluten to relax, making the dough easier to stretch without tearing.

11. Shape to Create Surface Tension

Good shaping is one of the secrets behind a tall, open sourdough loaf.

The goal is to create enough surface tension to support the dough while allowing the interior to expand during baking.

Too little tension can result in a flat loaf. Too much tension can restrict expansion.

How to improve it:
Build a smooth outer skin around the dough without aggressively compressing the interior.

The finished dough should feel structured and elastic while still retaining the gas developed during fermentation.

12. Don't Use Excessive Flour During Shaping

It can be tempting to cover everything with flour when working with sticky sourdough.

However, excessive flour can prevent the dough surfaces from sticking together during shaping.

This makes it more difficult to create proper surface tension.

How to improve it:
Use only enough flour to prevent sticking. A dough scraper and lightly floured hands are often more useful than covering the entire work surface with flour.

13. Use the Right Final Proof

After shaping, the dough needs a final period of fermentation before baking.

This can be done at room temperature or in the refrigerator.

Cold proofing is particularly popular because it slows fermentation and makes the dough easier to score.

How to improve it:
Judge the dough rather than relying exclusively on a fixed proofing time.

An under-proofed loaf can have excessive oven spring and a dense crumb, while an over-proofed loaf may spread and have limited oven spring.

14. Understand the Role of Scoring

Scoring is not merely decorative.

The cuts you make in the surface of sourdough bread provide controlled pathways for expansion during baking.

Without adequate scoring, the loaf may rupture at a weak point.

How to improve it:
Use a sharp bread lame or razor blade and make a confident cut at the appropriate angle and depth.

For a classic sourdough ear, a long score made at a shallow angle can encourage the surface to open dramatically.

15. Don't Score Too Deeply

Deep scoring can weaken the dough structure and prevent the loaf from opening cleanly.

How to improve it:
Use a controlled cut rather than trying to cut deeply into the loaf.

The exact depth depends on the dough, shaping, hydration, and scoring pattern, but a relatively shallow cut is usually sufficient for a main expansion score.

16. Steam Is Essential During the First Stage

Steam plays a crucial role in creating a beautiful sourdough crust and open crumb.

During the initial stage of baking, steam keeps the dough surface flexible for longer.

This allows the loaf to continue expanding before the crust sets.

Without sufficient steam, the crust can harden too quickly and restrict oven spring.

17. Use a Covered Cast Iron Bread Oven

One of the easiest ways to create the right baking environment at home is to use a preheated cast iron bread oven with a lid.

As the dough heats, water evaporates from the dough. The enclosed baking chamber traps this moisture, creating a naturally humid environment around the loaf.

This provides the steam needed for strong oven spring and helps produce a thin, crisp crust.

How to improve it:
Preheat your cast iron bread oven thoroughly before adding the dough.

Place the shaped sourdough loaf inside, cover it with the lid, and keep it covered during the initial stage of baking.

18. Don't Open the Lid Too Early

Opening a covered cast iron bread oven during the first stage of baking allows steam to escape.

This can reduce oven spring and cause the crust to set earlier than desired.

How to improve it:
Keep the lid closed during the initial high-steam phase. Remove it later in the bake when you want the crust to brown and become crisp.

19. Preheat Your Cast Iron Bread Oven Properly

The baking vessel needs to be hot enough to provide strong initial heat to the dough.

A properly preheated cast iron bread oven also helps maintain a stable baking environment when the relatively cool dough is introduced.

How to improve it:
Allow the cast iron bread oven to preheat fully before baking. Follow the temperature recommendations for your particular recipe and cookware.

20. Bake Until the Crust Is Fully Developed

A beautiful open crumb isn't enough if the loaf is under-baked.

Sourdough bread contains a considerable amount of water, and the interior needs enough time to set properly.

How to improve it:
Bake until the crust has developed a deep, rich color and the loaf feels properly baked. If you have a reliable instant-read thermometer, an internal temperature around 96–99°C can be a useful reference for many sourdough loaves.

21. Don't Cut Sourdough Bread Too Early

One of the hardest parts of sourdough baking is waiting.

The crumb continues to set as the loaf cools. Cutting into a very hot loaf can compress the crumb and make it appear gummy.

How to improve it:
Allow your sourdough bread to cool substantially before slicing. For many loaves, waiting at least one to two hours produces a noticeably better texture.

22. Look at the Crumb as a Diagnostic Tool

Professional bakers don't just admire the crumb—they use it to understand what happened during the bake.

The distribution, size, and shape of the holes can provide clues about fermentation, shaping, and baking.

A very dense crumb may indicate under-fermentation, weak gluten development, or insufficient hydration.

Very large holes directly beneath the crust combined with a dense lower crumb can sometimes indicate under-fermentation or shaping issues.

A uniformly tight crumb can suggest insufficient fermentation or excessive degassing.

How to improve it:
Use every loaf as feedback. Take note of your dough temperature, fermentation time, hydration, shaping technique, and baking conditions.

Small adjustments are often more useful than completely changing your recipe.

23. Don't Chase Huge Holes at Any Cost

An open crumb is visually impressive, but bigger holes do not automatically mean better sourdough.

An extremely open crumb can make the bread difficult to slice and less practical for sandwiches, butter, or toppings.

Professional bakers choose crumb structure according to the type of bread they are making.

How to improve it:
Aim for an airy, well-developed crumb that suits your bread rather than simply trying to create the largest holes possible.

24. Control Your Dough Temperature

Temperature has a major effect on sourdough fermentation.

A warm dough can ferment rapidly, while a cool dough may take considerably longer.

How to improve it:
Monitor your dough temperature and use it to help predict fermentation.

Rather than blindly following room-temperature timings, adjust fermentation based on the actual conditions in your kitchen.

25. Keep Your Process Consistent

Professional bakers get repeatable results because they control variables.

If the flour, hydration, dough temperature, fermentation time, shaping, and baking conditions change every time you make bread, it becomes difficult to identify what caused a particular result.

How to improve it:
Keep notes when experimenting with sourdough. Record flour, hydration, starter percentage, dough temperature, bulk fermentation duration, proofing time, and baking temperature.

Once you have a reliable baseline, change one variable at a time.

The Formula Is Only Half the Recipe

A sourdough recipe can give you precise quantities of flour, water, salt, and starter, but the numbers alone cannot guarantee an open crumb.

The real skill is learning how the dough behaves.

Two batches made with exactly the same ingredients can behave very differently depending on flour, temperature, starter activity, and fermentation.

This is why professional bakers pay close attention to the dough itself.

The Role of a Cast Iron Bread Oven in Open-Crumb Sourdough

A good fermentation process creates the gas and gluten structure needed for an open crumb.

The baking process then determines how effectively that structure can expand.

A cast iron bread oven with a deep lid creates an enclosed environment that naturally captures the moisture released by the dough. This provides the steam needed during the early stage of baking while the heavy cast iron helps maintain heat.

The combination of strong initial heat and trapped steam encourages oven spring, allowing the fermented dough to expand before the crust becomes rigid.

This is one reason covered cast iron bread ovens have become popular among home sourdough bakers.

A Simple Open-Crumb Checklist

Before baking your next sourdough loaf, check the following:

• Is your sourdough starter active?

• Is your flour strong enough for your chosen hydration?

• Has the dough developed sufficient gluten?

• Has bulk fermentation progressed far enough?

• Has the dough been handled gently?

• Did you create enough surface tension during shaping?

• Is the final proof appropriate?

• Is your scoring sharp and controlled?

• Is your cast iron bread oven fully preheated?

• Are you trapping steam during the first stage of baking?

• Are you allowing the bread to cool before slicing?

If the answer to all of these is yes, you're giving your dough the best possible conditions for an open, airy crumb.

Final Thoughts

The secret to an open sourdough crumb isn't one special ingredient or a single professional trick.

It is the result of many small decisions made correctly.

Strong flour provides the foundation. Proper hydration allows the dough to remain extensible. Fermentation creates gas and develops flavor. Gluten development gives the dough the strength to hold that gas. Gentle shaping preserves the internal structure. Scoring provides a controlled path for expansion.

Finally, intense heat and steam allow the loaf to transform inside the oven.

A preheated cast iron bread oven with a tight-fitting lid is particularly effective at creating the hot, humid environment needed during the first stage of baking. Once the lid is removed, the loaf can finish baking and develop its characteristic crisp, deeply browned crust.

The most important lesson is to stop thinking of open crumb as something you get from a recipe alone.

Learn to read your dough.

Once you understand fermentation, hydration, gluten development, shaping, scoring, steam, and baking, you can begin making adjustments based on what your dough is telling you.

That is the real skill behind consistently beautiful artisan sourdough bread.