Free tool
Sourdough crumb troubleshooter
Cut the loaf once it is fully cool and look at the slice. Answer seven questions about what you see and feel, and get a proof call, the faults that fit, and the one change worth making next bake.
Read the whole slice, not one hole
Every loaf leaves notes for the next one, and the cut face is where they are written. The mistake most bakers make is staring at the biggest hole. Big holes turn up in underproofed and overproofed loaves alike, so on their own they settle nothing. What settles it is the rest of the loaf: its shape, the base, the top crust, the crust color, the score and how the crumb feels when you press it.
That is why the troubleshooter asks seven quick questions instead of one. It covers the loaf's shape, the holes and where they sit, the base, the top crust, how the crumb feels, the crust color and the score. Each answer moves the proof call one way or the other, and the faults that fit are the ones that line up across several answers, not just one.
The proof scale it uses
The troubleshooter reads on the same five-step scale as the Loaf Scout app.
| Proof call | What the loaf usually shows | The change next bake |
|---|---|---|
| Underproofed | Dense band at the base, big tunnels in tight crumb, a gap under the top crust, a blowout at the side | Extend bulk 1 to 2 hours, until about 50 percent risen, domed and jiggly |
| A little underproofed | Open at the top, tighter toward the base, a burst on one side | 30 to 60 minutes more bulk, or a slightly longer final proof |
| Well proofed | Even crumb top to bottom, holes of many sizes, thin glossy walls, good height | Repeat it and write down what you did |
| A little overproofed | Lower and wider, a weak ear, a shade paler | End bulk 30 to 60 minutes sooner, or proof about 30 minutes less |
| Overproofed | Flat and spread, pale, lacy collapsed crumb, no ear | End bulk 1 to 2 hours sooner, or bulk cooler around 72F (22C) |
Most home bakers, especially early on, land on the under side more often than the over side: cool kitchens and young starters slow everything down, and recipe times are often written for a warmer room than yours. If the answers are split, the troubleshooter says so and points to the change that is safest to try first.
The faults it looks for
- Dense bottom: a compact, sometimes shiny band along the base. Usually underfermentation; a pot not fully preheated adds to it.
- Large tunnels: a few big channels surrounded by tight crumb. Usually underfermentation, or air folded in during loose shaping.
- Cavity under the crust: the top crust lifted away from the crumb, often called fool's crumb. A sign of underproofing that looks open at a glance.
- Gummy crumb: wet, shiny, squashes into paste. Most often the loaf was cut while still warm. If it is gummy when fully cool, the bake or the proof was short.
- Flat profile: spread sideways instead of up. Often overproofing, loose shaping or a very wet dough.
- Collapsed crumb: thin torn walls, a sunken top. The dough ran past its peak.
- Tight crumb: small, even, close-set holes. A firmer dough or more fermentation needed, and completely normal for whole wheat, rye and spelt.
- Pale crust, no ear, shaping lines: smaller notes about the bake, the score and the shaping, mostly about looks.
One lever, one change
The result ends with one lever to move next bake: bulk, proof, shaping, bake, hydration, starter, cooling or flour. Just one, on purpose. Change two things at once and the next loaf cannot tell you which one worked. If the bottom was dense, extend bulk by an hour next time and leave everything else alone. Then you will know exactly what that hour did.
If the loaf came out well, keep everything the same and write it down.
Try it
If the troubleshooter points at the water, check your dough's true hydration in the hydration calculator. Starter counted, it is often a few points wetter than the recipe line suggests.
Before you blame the bake
Cut too soon and almost any loaf looks gummy and dense. The center leaves the oven near the boiling point of water and keeps setting as it cools, so wait at least 1 to 2 hours for a regular loaf and longer for big or whole grain ones. If you cut it warm, the troubleshooter takes that into account before it calls the fermentation.
Look in daylight, straight on, with the loaf cut through the middle with a serrated knife. Light, angle and a warm knife all change how a crumb looks. Your own eyes, nose and the poke test still count, and so does the way the dough felt before it went in.
Read more in the sourdough crumb, read it like a baker, underproofed vs overproofed and why is my sourdough dense and gummy.
Sources
The proof scale, the faults and the fixes come from the Loaf Scout app's guide, which draws on The Perfect Loaf's bulk fermentation and proofing guides; the internal temperature and cooling advice follow The Perfect Loaf's baking guide. Each linked guide names its sources in full. The troubleshooter is a set of fixed rules applied to your answers, and it runs in your browser.
Questions
How can I tell if my sourdough is underproofed or overproofed?
Read the whole loaf. Tall with a burst, a dense base, tunnels or a gap under the crust points to under. Flat, pale and lacy with no ear points to over. Big holes alone do not decide it.
Why does my sourdough have big holes but a dense crumb?
That is the classic look of underproofing: too little gas spread through the dough, so the oven blows a few large channels while the crumb around them stays tight. Extend bulk by 1 to 2 hours next bake.
Why is my sourdough gummy inside?
Most often it was cut while still warm. Wait at least 1 to 2 hours. If it is gummy even when fully cool, bake until the center reads about 205 to 210F (96 to 99C) and look for signs of underproofing.
Is a tight crumb a fault?
Not always. Whole wheat, rye and spelt loaves bake tighter by nature, and a tight, even crumb makes great sandwich bread. In a white loaf, a little more water or a longer bulk opens it up.
Why change only one thing next bake?
Because then the next loaf tells you what that change did. Change bulk, hydration and the bake at once and you will not know which one helped or hurt.
Is the troubleshooter the same as the app's photo read?
No. The troubleshooter applies fixed rules to your answers. The app reads one photo of the cut face. Loaf Scout gives an AI read of one photo; your own eyes, nose and the poke test still count.