Hydration (baking)

Hydration is the ratio of water (or other liquid) to flour in a dough, expressed as a percentage. In baker’s percentages (where flour is always 100%), a dough with 600 g water and 1000 g flour has 60% hydration.

Typical hydration ranges for common breads:

• Stiff dough (bagels, English muffins): 50-60%
• Standard bread (sandwich loaf, baguette): 60-70%
• Artisan high-hydration (ciabatta, focaccia, sourdough): 70-85%
• Very high hydration (some sourdough styles, brioche-adjacent): 85-100%+

Higher hydration produces a more open crumb (larger irregular holes), a chewier texture, a shinier crust. It’s also more difficult to handle — the dough is sticky and slack, requires gentler techniques (stretch-and-folds rather than kneading), and benefits from longer fermentation.

Why baker’s percentages rather than ratios: when scaling a recipe, baker’s percentages stay constant. A 60% hydration dough is 60% whether you’re making 500 g of dough or 50 kg. The math: hydration % = (water mass / flour mass) × 100.

Hydration interacts with flour protein content. Higher-protein bread flour can absorb more water before becoming unworkable than all-purpose flour, which is why pro bakers prefer it for high-hydration breads. Wholewheat absorbs even more.

Worked example

Make a 75% hydration sourdough: 500 g bread flour, 375 g water, 100 g levain (50 g flour + 50 g water at 100% hydration), 10 g salt. Total flour in the dough = 500 + 50 = 550 g. Total water = 375 + 50 = 425 g. Effective dough hydration = 425 / 550 = 77.3% — slightly higher than the “75%” the recipe headline claims, because the levain’s water gets included. Now compare to a 65% hydration sandwich loaf: 500 g flour, 325 g water — much stiffer, easier to shape, tighter crumb after baking. Push the same flour to 85% hydration (425 g water) and the dough becomes nearly pourable, requires bench scrapers and wet hands to handle, ferments faster, and produces the open lacework crumb that Instagram bread photography popularised. The same flour, three different breads, just water-ratio away.

When and why it matters

Hydration matters because it determines almost everything about bread texture: crumb openness, crust thickness, fermentation speed, and shapability. The most common home-baker mistake is following a percentage that assumed bread flour, then using all-purpose flour — the lower-protein flour cannot hold the same water content and the dough turns to soup. The fix is to drop hydration 3-5 percentage points when substituting all-purpose for bread flour. The second mistake is forgetting that whole-grain flours absorb more water than white flours; converting a 75% white-flour recipe to 100% whole wheat without raising hydration to ~85% produces a dense brick. The third is humidity-blindness: in damp climates (London winters, Pacific Northwest), flour itself contains ~14% water and the dough effectively hydrates higher than the recipe expects. In dry climates (Phoenix, Madrid summers), flour can be ~10% water and doughs run dry. Reference: The Fresh Loaf — Baker’s percentage handbook.

Total dough hydration includes every liquid, not just water: milk, eggs, oil, and softened butter all contribute to the hydration calculation. A typical large egg is about 75% water, so a brioche recipe with 1000 g flour, 200 g water, and 4 eggs has total hydration of roughly (200 + 4 × 50 × 0.75) / 1000 = 35% — much drier than the “200 g water” reading suggests. Misreading the hydration is the most common reason a bread recipe behaves unexpectedly when adapted from a different source: a recipe quoting “65% hydration” counting only water is a different dough from one quoting “65% hydration” total.

Why hydration matters for fermentation rate: yeast metabolism speeds up at higher hydration because the dough environment is more mobile — nutrients diffuse faster, gas bubbles expand more readily. A 75% hydration dough ferments roughly 20-30% faster than a 60% hydration dough at the same temperature. This is the reason high-hydration sourdough recipes often specify shorter bulk fermentation times despite the more open crumb. Conversely, very stiff doughs (50% hydration bagels) need either longer fermentation or warmer temperatures to develop the same flavour. Related: cooking converter, autolyse. Reference: Calvel R, Le Goût du Pain (1990).