This loaf looked incredible.

Seriously.

Beautiful crust. Great color. Nice oven spring.

The score opened.

You even got a little ear.

You waited for it to cool, grabbed the bread knife and started slicing.

First slice… beautiful.

Second slice… looking good.

Third slice…

WHAT IS THAT?

There is a hole.

Not a normal sourdough hole.

This thing has square footage. 😂

You could store your car keys in it.

You could install shelving.

With current housing prices, you could probably rent it.

Meanwhile, the rest of the crumb is relatively dense.

Welcome to sourdough tunneling.

🐿️ FIRST: BIG HOLES AREN'T ALWAYS BAD

Sourdough isn't sandwich bread. An artisan loaf often has an irregular crumb.

Some holes are larger. Some are smaller. That's completely normal.

But we're not talking about normal variation.

We're talking about THE CAVE.

The giant tunnel surrounded by areas of much denser crumb can give you useful information about what happened during fermentation and shaping.

🕵️ SUSPECT #1: UNDERFERMENTATION

When dough is underfermented, gas production and distribution may be uneven.

You can end up with:

• dense crumb
• tight areas
• random large pockets
• poor overall expansion
• tunnels beneath the crust

This is where beginners get confused.

They see the giant hole and think:

Meanwhile, approximately 87% of the loaf has the texture of a kitchen sponge. 😂

Look at the entire crumb—not just the biggest hole.

🔬 WHAT UNDERFERMENTED CRUMB CAN LOOK LIKE

Underfermented sourdough can sometimes show a combination of large irregular tunnels, dense areas and tight crumb.

That's different from a reasonably even distribution of open pockets throughout the loaf.

⏰ STOP FERMENTING BY THE CLOCK ALONE

Our standard Squirrelly Girl bread process generally uses a 2–4 hour room-temperature bulk fermentation after the stretch-and-fold stage, followed by shaping and an overnight cold ferment.

But that window is still dough-dependent.

Your kitchen temperature matters.

Your dough temperature matters.

Your starter strength matters.

Your flour matters.

Don't simply say:

“Three hours have passed. We're done.”

Look at the dough.

👀 WATCH YOUR DOUGH DURING BULK FERMENTATION

Look for a combination of signs:

• increased volume
• visible bubbles
• a lighter, aerated feel
• improved structure
• fermentation activity
• some jiggle and life

You are looking for dough that has clearly changed from the dense mass you started with.

If it still looks like it just left the mixing bowl, the timer doesn't get the final vote.

🫧 SUSPECT #2: YOU TRAPPED A GIANT AIR BUBBLE

Sometimes the culprit is simpler.

You created a giant bubble.

Then you carefully preserved it.

Then you baked it.

😂

During shaping, unusually large air pockets can sometimes become trapped inside the loaf.

We don't want to aggressively flatten every bubble out of properly fermented sourdough.

But if you see an enormous bubble forming during shaping, you don't need to treat it like a protected species.

🤲 “BUT I THOUGHT I WASN'T SUPPOSED TO DEFLATE THE DOUGH!”

Correct.

And incorrect.

Welcome to sourdough. 😂

You generally don't want to smash properly fermented dough flat and destroy all the gas you've created.

But gentle handling doesn't mean never touching a large bubble.

Preserve the overall aeration while dealing gently with unusually large pockets.

🌀 SUSPECT #3: YOUR SHAPING CREATED A POCKET

Shaping isn't only about making the loaf round or pretty.

You're organizing the dough.

If folds are uneven or large pockets become trapped between layers, internal voids can form.

Imagine folding a blanket with a balloon trapped inside.

Now bake the blanket.

Actually, don't. Terrible recipe. 😂

Good shaping helps create structure, tension, organization and more consistent gas distribution.

💪 SURFACE TENSION MATTERS

During final shaping, we want enough surface tension to help the loaf hold its form.

Too little tension and the dough may spread.

Too aggressive and you may tear or overly degas the dough.

At first you're thinking:

“How tight is tight?”

Eventually your hands just know.

That's sourdough's favorite teaching method:

Make you confused approximately 37 times until muscle memory takes over. 😂

🌾 SUSPECT #4: YOUR DOUGH STRENGTH WAS UNEVEN

Gluten structure helps trap fermentation gases throughout the dough.

That's one reason stretch-and-folds matter.

As the dough develops, you may notice it becoming:

• smoother
• more elastic
• stronger
• easier to handle
• better at holding shape

If your dough stays very weak and loose, the final crumb may reflect that.

💧 SUSPECT #5: YOU CHASED HIGH HYDRATION

You saw a gorgeous loaf online with huge holes.

Someone said:

“80% hydration.”

And you thought:

“I WANT THAT.”

So you added more water.

And more water.

Now you're trying to shape something with the structural integrity of pancake batter. 😂

Higher hydration can contribute to a more open crumb, but water alone doesn't create good crumb.

You still need fermentation, gluten development, dough strength, good shaping and proper handling.

🍞 OPEN CRUMB IS NOT A COMPETITION

At some point, sourdough internet culture convinced everyone that the goal of bread is to contain the least possible amount of bread.

😂

Huge holes everywhere.

Massive chambers.

Crumb so open your butter falls straight through onto your pants.

Beautiful for photographs.

Slightly inconvenient for sandwiches.

There is absolutely nothing wrong with a moderately open, even crumb.

The goal isn't the biggest holes possible. The goal is well-fermented, delicious bread.

🧈 YOUR BUTTER WOULD ALSO LIKE A WORD

You toast your gorgeous ultra-open sourdough.

You add butter.

The butter melts.

Straight through the bread.

Now your plate is buttered.

Your table is buttered.

Possibly your leg.

😂

There comes a point where crumb becomes architecture.

🔪 CUT MORE THAN ONE SLICE

You slice into the loaf.

GIANT HOLE.

You immediately declare:

Keep slicing.

Sometimes one section contains a weird pocket while the rest of the loaf looks completely reasonable.

Bread is three-dimensional.

One slice is not always the whole story.

This is also an excellent excuse to keep eating bread in the name of research. Science. 😂

🧪 YOUR CRUMB IS A FERMENTATION REPORT CARD

🥶 DON'T FORGET THE COLD FERMENT

After bulk fermentation and shaping, our standard bread process moves the loaf into the refrigerator for an overnight cold ferment.

This helps develop flavor and makes chilled dough easier to score.

But the refrigerator doesn't magically repair dough that wasn't properly fermented beforehand.

Cold fermentation is part of the process. It is not a sourdough witness-protection program. 😂

🧠 THE BIGGEST SKILL IS LEARNING TO READ DOUGH

Beginners ask:

“How many hours?”

Experienced bakers often ask:

“What does the dough look like?”

That's the transition.

Eventually you begin recognizing fermentation, strength, aeration, elasticity and readiness.

You stop needing the dough to follow an exact script.

You start responding to what it's actually doing.

📋 THE GIANT HOLE CHECKLIST