What hydration means
Hydration is the weight of water in a dough divided by the weight of flour, written as a percentage. A dough with 1,000 g of flour and 700 g of water is 70% hydration. That's it.
Bakers use this because it scales. A 70% dough behaves like a 70% dough whether you're making one loaf or fifty, so once you know how a hydration level feels and bakes, you can apply it to any batch size. It's part of a wider system called baker's percentages, where every ingredient is expressed as a percentage of the total flour.
How to calculate it
Hydration % = water ÷ flour × 100
Or work backwards from a target: water = flour × hydration ÷ 100. For 500 g of flour at 75%, you need 375 g of water.
The same approach works for salt (usually 2% of the flour) and starter (commonly 15–25%). A typical country loaf looks like this:
| Ingredient | Baker's % | For 500 g flour |
|---|---|---|
| Bread flour | 100% | 500 g |
| Water | 72% | 360 g |
| Starter (100% hydration) | 20% | 100 g |
| Salt | 2% | 10 g |
The starter catch: true hydration
A sourdough starter is itself flour and water. A 100% hydration starter is half flour, half water by weight, so 100 g of starter adds 50 g of flour and 50 g of water to the dough.
In the loaf above, the true hydration is (360 + 50) ÷ (500 + 50) = 74.5%, not 72%. It's a small shift that shows up in how slack the dough feels, and it's bigger with stiff or very liquid starters. Our bread hydration calculator works this out automatically.
Which hydration should you use?
| Hydration | Dough feel | Typical result |
|---|---|---|
| 55–62% | Firm, smooth, easy to shape | Bagels, pretzels, tight sandwich crumb |
| 63–70% | Soft, slightly tacky | Sandwich loaves, beginner sourdough |
| 70–78% | Sticky but manageable | Classic sourdough with moderate holes |
| 78–85% | Slack, needs folds and practice | Open, glossy, irregular crumb |
| 85%+ | Very wet, almost pourable | Ciabatta, focaccia |
How flour changes everything
The same hydration feels different with different flours. Whole wheat and rye contain bran and other components that soak up more water, so a 75% whole wheat dough feels stiffer than a 75% white dough. If you swap in a significant amount of whole grain flour, add roughly 5–10% more water to get a similar feel.
Higher-protein bread flour also absorbs a little more water and builds stronger gluten, which helps hold a wetter dough together. Lower-protein all-purpose flour gets slack sooner, so drop the hydration a few points if your dough is spreading.
Handling wetter doughs
- Hold back some water. Keep 5–10% of the water aside and add it after the dough has started developing gluten. Bakers call this bassinage.
- Use stretch-and-folds. Three or four sets during the first couple of hours of bulk fermentation build strength without kneading.
- Wet your hands, not the bench. Water keeps dough from sticking to you without adding raw flour to the loaf.
- Watch the dough, not the clock. Bulk fermentation is done when the dough has grown noticeably, feels airy, and shows bubbles at the edges.
Gear that makes wet dough easier
A bench scraper, a banneton and a Dutch oven do most of the heavy lifting. See sourdough kits →
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