From grimoire
Guides the sourdough bread-making process from starter maintenance through baking, including fermentation, shaping, and achieving open crumb and crackly crust.
How this skill is triggered — by the user, by Claude, or both
Slash command
/grimoire:design-sourdough-processThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Maintain a live starter, develop gluten through folding, cold-retard for flavour, and bake in a sealed vessel to produce a well-risen loaf with crackly crust and open crumb.
Maintain a live starter, develop gluten through folding, cold-retard for flavour, and bake in a sealed vessel to produce a well-risen loaf with crackly crust and open crumb.
Adopted by: Tartine Bakery (Chad Robertson) popularised the modern sourdough method — now used by artisan bakeries worldwide and home bakers following Robertson's open-crumb, high-hydration approach. King Arthur Baking's sourdough guide is the reference used by the largest sourdough community in the US. The Bread Lab (WSU) and The Modernist Bread team validated the science behind long cold fermentation and Dutch oven baking through controlled experiments.
Impact: A well-executed sourdough loaf requires no commercial yeast, no preservatives, and produces a more digestible bread than commercial sandwich bread (longer fermentation partially breaks down phytic acid and some gluten proteins). Home baking cost is ~$0.50–1.00/loaf vs. $8–12 for equivalent artisan bread. Mastering the process gives full control over flavour (more/less sour), crumb structure (open vs. tight), and crust (thin/thick).
Why best: The Robertson method — autolyse, stretch-and-fold in lieu of kneading, long cold retard — produces more flavour and better crumb structure than short-mix, room-temperature methods. The Dutch oven replicates commercial deck ovens: trapped steam keeps crust extensible during oven spring; removing the lid browns and crisps it. These steps are not arbitrary; each has a documented biochemical function.
Sources: Robertson, Tartine Bread (2010) — bulk fermentation and fold timing; Hamelman, Bread (2nd ed., 2004) — gluten development science; Myhrvold & Migoya, Modernist Bread vol. 2 (2017) — heat transfer and crust formation; King Arthur Baking (2023) — starter maintenance ratios
A starter is a live culture of wild yeast and lactic acid bacteria. Without a healthy starter, nothing else works.
Feeding ratio: 1:5:5 (1 part starter : 5 parts flour : 5 parts water by weight). Use unbleached all-purpose or bread flour; whole wheat or rye accelerates fermentation (more nutrients for bacteria).
Feeding schedule:
Float test: Drop a teaspoon of starter into water. If it floats, it has enough gas to leaven bread. If it sinks, feed again and wait.
Signs of a healthy starter: Doubles in 4–8 hours after feeding; smells pleasantly sour and yeasty (not vinegary or acetone-like); shows a domed surface with visible bubbles.
Autolyse is a 30–60 minute rest after mixing flour and water before adding starter and salt. It allows gluten to hydrate and partially develop without kneading, producing more extensible dough.
Basic ratio (one loaf, ~900g baked weight):
| Ingredient | Weight | Baker's % |
|---|---|---|
| Bread flour | 400g | 80% |
| Whole wheat flour | 100g | 20% |
| Water (lukewarm, ~80°F) | 375g | 75% |
| Active starter | 100g | 20% |
| Salt | 10g | 2% |
Bulk fermentation develops gluten, builds flavour, and raises the dough. For a 75% hydration dough at 75°F, bulk fermentation takes approximately 4–5 hours.
Stretch and fold: Every 30 minutes for the first 2 hours (4 total sets).
Signs bulk is complete:
Temperature matters: Colder dough ferments slower. If your kitchen is 65°F, add 1–2 hours. If 80°F, subtract 1 hour. A proofing box or oven with just the light on (~78°F) is ideal.
Turn the dough onto an unfloured surface. Using a bench scraper and your other hand, drag the dough toward you in a circular motion, building tension on the surface. The dough should tighten into a ball. Rest 20–30 minutes uncovered (bench rest).
Flour the surface lightly. Flip the dough. Stretch it gently into a rough rectangle. Fold the sides in, then roll it toward you into a tight cylinder (batard) or pinch the edges into a ball (boule). Place seam-side up in a well-floured banneton (proofing basket) or a bowl lined with a heavily floured cloth. Dust the top of the dough with flour.
Cover tightly with plastic wrap or a shower cap. Refrigerate 12–16 hours (up to 24 hours).
Cold fermentation develops flavour: the long, cold environment favours lactic acid bacteria that produce acetic acid (the sharp, tangy notes) in addition to lactic acid (the mild, yogurt-like notes). Longer cold retard = more sour flavour. Baking cold dough directly from the fridge also produces better oven spring and makes scoring easier.
Place a lidded Dutch oven (5–7 qt, cast iron) in the oven. Preheat to 500°F (260°C) for at least 45 minutes. The Dutch oven must be screaming hot.
Bake schedule:
The loaf is done when the internal temperature reaches 205–210°F (96–99°C) and the crust is a deep mahogany brown. Tap the bottom — it should sound hollow.
Transfer the loaf to a wire rack. Cool for a minimum of 1 hour, ideally 2. Cutting hot bread compresses the crumb and releases steam that would otherwise set the interior structure. The crumb continues cooking from residual heat after you remove it from the oven.
Standard Tartine-method country loaf:
High-hydration loaf (for very open crumb): Increase water to 80–82% hydration. Use wet hands for all folds. Expect stickier dough throughout; do not add flour. Requires confident shaping — the dough is extensible but fragile.
Faster same-day loaf: Increase starter to 30%, ferment at 80°F. Bulk will finish in 3–3.5 hours. Flavour will be milder (less acetic acid). Skip cold retard; shape, proof at room temperature 1–2 hours until dough passes poke test (indent springs back slowly), then bake.
Under-fermented bulk (most common): Dough that hasn't risen enough is dense, gummy, and tastes raw. Cause: starter not active, kitchen too cold, or bulk cut short. Signs: loaf doesn't spring in the oven; crumb is dense and gooey.
Over-fermented bulk: Dough is sticky, slack, won't hold shape. The gluten network has been degraded by enzymatic activity. Cause: too warm, too much starter, bulk too long. Prevention: watch the dough, not the clock.
Not flouring the banneton enough: Dough sticks and tears during the flip. Use 50/50 rice flour and all-purpose flour (rice flour doesn't absorb moisture and prevents sticking far better than all-purpose alone).
Scoring too shallow or too straight: A shallow score seals; a 90° angle score traps the blade. Score at 30–45° angle, at least ¼ inch deep, in a single confident motion.
Cutting before cooling: The interior is still steaming. Cutting hot bread produces a compressed, gummy crumb. Wait the full hour minimum.
npx claudepluginhub jeffreytse/grimoire --plugin grimoireDesigns bread scoring cut patterns, blade angles, and depth to control oven spring and crust formation. Useful when scoring sourdough or enriched doughs before baking.
Runs a multi-phase pipeline (cook→press→age→cure→age→cure→age) with fresh-context isolation per phase using sub-agents. For executing approved specs autonomously without cross-phase contamination.
Teaches cooking through culinary principles, food science, and flavor architecture. Covers technique, troubleshooting, menu planning, and cultural cuisine.