Sourdough Hydration & Timing Calculator

Sourdough Baking Guide

Understanding Hydration

Sourdough hydration is water as a percentage of flour by weight. 65–70%: beginner-friendly, easier to shape, tight crumb structure. 72–76%: balanced — the classic country loaf range, open crumb, good rise. 78–85%: high hydration, more open crumb, more challenging to handle. 85%+: very slack dough, requires good technique, typically baked in a tin. Starter hydration also affects the total — if using a 100% hydration starter (equal weights flour and water), half the starter weight counts as water.

Temperature and Fermentation

Fermentation rate roughly doubles for every 10°C rise in temperature (Q10 rule). At 18°C, bulk fermentation may take 12 hours. At 24°C, the same dough may be ready in 4–5 hours. This is why recipes saying 'bulk ferment for X hours' are unreliable without knowing room temperature. A dough thermometer is more useful than a clock. Look for 50–75% increase in volume, a domed surface with bubbles, and a jiggly but not slack texture.

The Fold and Coil Process

Rather than kneading, sourdough develops structure through a series of stretch-and-fold or coil-fold sets during bulk fermentation. Typically 4–6 sets in the first 2 hours, then leaving the dough alone to ferment fully. Each fold builds gluten structure and traps gas. Under-folding produces a flat, dense loaf. Over-folding can degas the dough. The dough should feel noticeably stronger and more cohesive after the first few folds.

The Bake — Dutch Oven Method

Baking in a preheated Dutch oven (lidded cast iron) traps steam from the dough, producing an open ear and blistered, crackled crust — the hallmark of a good sourdough. Preheat the Dutch oven in a 250°C oven for 45–60 minutes. Bake covered for 20 minutes (steam phase), then remove lid and bake at 220°C for a further 20–25 minutes until deep mahogany brown. Internal temperature should reach 96–98°C. Let cool for at least 1 hour before cutting — the crumb continues setting as it cools.