Sourdough Bread: Crumb, Crust, and Ferment
Move beyond dense, unpredictable loaves by mastering dough tension, fermentation cues, and heat physics. Learn to diagnose crumb defects, handle high hydration, and steer microbial activity for explosive oven spring.
Like Duolingo, but for Sourdough Bread: Crumb, Crust, and Ferment. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
26 levels across 4 sections, about 52 minutes end to end, roughly 10 days at five minutes a day. It moves through Diagnosing and Fixing the Bake, Dough Dynamics: Hydration and Gluten, Fermentation Control and Shaping, and Controlling the Microbial Engine. It assumes you already know the basics.
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Key ideas in Sourdough Bread: Crumb, Crust, and Ferment
- Thick cast iron absorbs heat slowly and lags behind air temperature
- Saturated thermal mass dumps rapid conductive heat to drive the initial burst
- Insufficient base heat leaves a pale, gummy bottom while the top sets
- Trapped steam condenses on dough to keep the outer skin flexible and elastic
- Without humidity, the exterior starch gelatinizes prematurely into a rigid shell
- Tucking ice under parchment shields the dough bottom from thermal shock
- Cold dough firms solidified fats and gelatinized starches to resist slumping
- Warm, high-hydration dough relaxes rapidly and puddles horizontally on hot metal
- Chilled dough produces a stiffer outer skin that cuts cleanly without snagging
- A 30 to 45 degree tilt cuts an asymmetric lip beneath the dough surface
- Vertical 90 degree cuts pull outward equally on both sides into an open valley
- Steam forces expansion beneath the undercut flap, peeling it upward into an ear
- The closed, humid phase must run first to let gas expand before crust solidifies
- Removing the lid mid-bake vents trapped moisture to let dry heat take over
- Dry radiant heat browns starches and produces micro-blisters on the crust
- Underfermented dough traps expanding steam in isolated pockets rather than aerating evenly.
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Sourdough Bread: Crumb, Crust, and Ferment the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
Why do you want your Dutch oven fully heat-saturated before loading your dough?
Get it right to open this lesson and 25 more in the app.
Where Sourdough Bread: Crumb, Crust, and Ferment takes you
- 1
Diagnosing and Fixing the Bake
- Immediate Levers for Explosive Oven Spring
- Diagnosing Crumb Structure and Baking Faults
- 2
Dough Dynamics: Hydration and Gluten
- Hydration Ratios and Flour Absorption
- Building Gluten Tension Through Gentle Handling
- 3
Fermentation Control and Shaping
- Reading Bulk Fermentation Beyond the Clock
- Shaping Architecture and Banneton Tension
- Retardation and Acid Modulation
- 4
Controlling the Microbial Engine
- Starter Ecology and Levain Kinetics
4 sections · 8 units · 26 levels. Built to play, not to enroll.
You pick the voice
Sourdough Bread: Crumb, Crust, and Ferment is taught in the The Bestie style: your friend who just gets it. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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