The Complete Guide to Sourdough Hydration

If you've ever followed a sourdough recipe and ended up with dough that was either a crumbly brick or an unworkable puddle, hydration is almost certainly the culprit. Understanding hydration is the single most important step in going from following recipes to actually understanding what you're doing.

What does hydration mean in sourdough?

Hydration is the ratio of water to flour in your dough, expressed as a percentage of the flour weight. If a recipe calls for 500g of flour and 375g of water, the hydration is:

375 ÷ 500 × 100 = 75% hydration

That's it. Nothing more complicated than that. The reason bakers express it as a percentage — rather than a ratio or a fraction — is that it makes scaling and comparing recipes much easier. A recipe at 75% hydration is 75% hydration whether you're making one loaf or ten.

How hydration affects your bread

Hydration changes almost everything about how the dough behaves and what the final bread looks like.

Low hydration (60–70%)

The dough is stiff and easy to handle. It holds its shape well, making it forgiving for beginners. The crumb (the inside of the bread) will be tighter and more even — ideal for sandwich loaves or toast bread. The crust tends to be thinner and less crackly.

Medium hydration (70–78%)

The dough is soft and slightly tacky but still manageable. This is the sweet spot for most home bakers — enough water for a nice open crumb and good crust, without being so wet that shaping becomes a fight. Most popular sourdough recipes sit in this range.

High hydration (78–90%+)

The dough is sticky, slack, and challenging to shape. In the right hands it produces the dramatic open crumb and blistered crust you see in artisan bakeries. But it requires strong technique: confident shaping, proper gluten development through folds, and a well-fermented dough. A poorly fermented high-hydration loaf will spread flat and dense.

Hydration reference table

Hydration	Dough texture	Difficulty	Best for
60–65%	Stiff, easy to knead	Beginner	Sandwich loaves, bagels
65–72%	Smooth, slightly tacky	Beginner	Everyday loaves, bâtards
72–78%	Soft, needs some technique	Intermediate	Artisan boules, baguettes
78–85%	Sticky and slack	Advanced	Open-crumb country loaves
85%+	Very wet, almost pourable	Expert	Ciabatta-style, extreme open crumb

Does higher hydration always mean better bread?

No — and this is a common misconception. High-hydration bread became fashionable partly because photos of extremely open crumbs went viral. But an open crumb is not always desirable. A sandwich loaf needs a tight, even crumb so your toppings don't fall through. A pizza crust should be chewy and structured. "Better" depends entirely on what you're making.

More importantly, high-hydration doughs are less forgiving. If your starter isn't active enough, your bulk fermentation timing is off, or your shaping technique is weak, a 85% dough will punish all of those errors. A 72% dough is far more likely to produce a good loaf even when things aren't perfect.

Start lower. Work your way up. Once you can consistently produce a good loaf at 72%, bumping to 76% will teach you a lot. Jumping straight to 85% before you understand fermentation usually produces frustrating results.

How your flour affects the hydration you can use

Different flours absorb water differently, which is why the same hydration percentage can feel completely different depending on what's in the bag.

• High-protein bread flour (12–14% protein) — absorbs more water, produces more gluten, can handle higher hydration well
• All-purpose flour (9–11% protein) — absorbs less water; a recipe designed for bread flour will feel wetter if you substitute AP flour
• Whole wheat flour — the bran absorbs a lot of water; adding even 20% whole wheat to your blend often requires adding 3–5% more water to get the same feel
• Rye flour — extremely absorbent; rye-heavy doughs can hold very high hydration but produce a dense, sticky crumb by nature
• Spelt flour — a weaker gluten structure than wheat; keep hydration lower than you would with bread flour or the dough will break down

Adjusting hydration in a recipe

You don't need to follow a recipe's hydration exactly. If a recipe calls for 78% and you're a beginner, there's nothing wrong with dropping it to 72% for your first few bakes. The bread will still be delicious — just with a slightly tighter crumb.

Use our sourdough calculator to enter any recipe and adjust the hydration with a single input. It recalculates the water automatically while keeping everything else in proportion.

The hydration of your starter matters too

Your sourdough starter contains both flour and water — usually in a 1:1 ratio by weight (100% hydration). That means the starter you add to your dough is already contributing to the overall hydration. A recipe that calls for 100g of 100% hydration starter is actually adding 50g of flour and 50g of water to your dough.

If your starter is a different hydration than the recipe assumes, the actual dough hydration will be different from what's written. Our calculator handles this automatically — see the starter hydration guide for the full explanation.