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Opening up about open crumb

Images of bread with large holes across the cut surface ‘crumb’ are everywhere across social media, blogs, and video sharing platforms.
For many aspiring home cooks an open crumb loaf is their aspirational sourdough goal; for others it is an impractical to eat and over-complicated to make style of a basic food overtaken by trendy appearances.
This blog is for the former group.
If you are wondering what I think… I enjoy making a wide variety of breads and styles. I try to reflect this on our social media.

Like most topics, whole books could be written about it (see book recommendation at the end*). This blog is a quick guide to help anyone desiring to open their bread crumb a bit more. It’s important to note that there are varying degrees of openness and the techniques need to be adjusted to achieve the desired result.

There may be different reasons why your loaf crumb is not what you are wanting to achieve. So, some of these may help, some may not be applicable. They are written in roughly the order they happen in the bread-making process. The advice is generally relevant to both sourdough and long-fermented instant (bakers) yeast breads.

First and foremost (if making sourdough bread), one of the critical factors is a highly active, but not over-fermented, sourdough starter (for my student’s reference: stages 1 & 2). If your sourdough starter (some refer to this as levain) is excessively fermented the build up of acids and enzyme activity will break down the flour structure, resulting in a denser crumb.

If it is accessible for you, try a strong (high protein) flour. For example, Flinders Premium Grains high-protein flour or Laucke Flour Mills Euro flour are two we have available. These can form a stronger gluten network which can trap more gas in the dough.

For the final dough, use slightly cooler water and allow the dough to bulk ferment a bit longer after the final fold during bulk ferment. Adjust to suit your kitchen temperatures.

You can increase the water in the final dough to achieve a stretchier dough, especially advised if using the stronger flours above. A more extensible dough will allow the gas bubbles to elongate, thus having an open crumb texture. However, if the handling of the dough is rough, the wetter dough will be denser. So, a balance between water content and gentle dough handling is needed.

Try adding an ‘autolysis’ (pronounced “auto-lees”—that’s my Australian pronunciation!). This French technique involves mixing the flour and most of the water in the final dough until hydrated, cover and allow to rest 30-60mins, then mix in salt and starter and mix as normal. During the rest, the gluten begins to form, and enzymes begin to work. Usually, the mixing time can be reduced. Some people swear by this technique, some think it is a waste of time! I generally do not bother, but it can be helpful if the goal is an open crumb.

Mix the dough longer, especially if mixing by hand. This will form better gluten structure, help the dough absorb water better, and incorporate more gas bubbles.

Add a little bit of water near the end of mixing. This last-minute addition of water gets between the gluten network which opens the dough structure a bit more.

Use a wide bowl/container for the bulk fermentation; something that will allow the dough to spread out. This will allow the dough to stretch more, which help give longer air bubbles, which can mean a more open crumb.

Ensure the bulk fermentation is active and gassy. However, the more gas-filled the dough during bulk fermentation the denser the air bubbles will be, so the final shaping will require less handling.

Handle the dough gently during folds and dividing (if applicable) and shaping. Keep the gas in the dough because these gas bubbles are what will eventually give the open crumb texture.

When shaping, avoid knocking gas out of the dough. And do not fold the dough over too many times during shaping, shape lightly. The more the dough is folded over the more the dough is compressed, and the gluten structure tightened. The dough needs to be able to stretch freely during the final rise (proof) and baking.

Make a free-form loaf, not a tin (pan) loaf. A banneton is helpful to support the dough while rising. The dough in a loaf pan is more compressed, so more difficult to form an open crumb. Ensure the dough in the banneton has space to expand a bit too. 

Ensure the final rise (proof) is not excessive. If over-proofed the texture can collapse and be dense. However, if under-proofed (and under-fermented throughout the sourdough starter-bulk ferment-final rise stages) the dough can have holes but dense crumb area around the gas bubble holes. This is not desired either. At the risk of repeating myself, a balance is required.

How the risen dough is cut/slashed/scored before baking also makes a difference to final crumb texture because it effects how the loaf expands. A single cut down the center of the loaf typically allows the dough to expand most widely which helps open the texture. Interestingly, if an open texture is not the goal (or, for example, if you suspect the loaf is over-risen) you can adjust the oven expansion by cutting other ways to limit the expansion.

When baking, a preheated pot or baking stone/steel with plenty of initial moisture (steam) is beneficial to assist the loaf to expand fully. Baking in a ‘dutch oven’ or with a bowl over the loaf on a pizza stone or other speciality baking pan usually give best results due to the immediate heat radiating through the dough and the doughs own moisture being trapped for the first third or so of the bake.

Let the baked loaf cool, do not slice it hot from the oven. The internal of the loaf is hot and the starches and proteins are setting and will compress if sliced warm.

If an open crumb is your goal, hopefully these will help!

*For much more detailed learning, one of the few resources I highly recommend (no affiliation) is the eBook Open Crumb Mastery by baker Trevor J. Wilson. Lots of the advice in this blog is based on my learning and subsequent baking using the principles from this book. It is dense with written content but with a very readable style. It is aimed at intermediate professional and home bakers and offers an excellent overview of bread-making, especially as it applies to achieving an open crumb.