05/27/2026
This makes so much more sense than anyone has explained it.
Hydration is one of the most important concepts in sourdough bread-making, and one of the most misunderstood. If you have ever followed a recipe exactly but still ended up with dough that felt too dry or far too sticky, you are not alone, and this post is for you.
Walk with me as I break it down properly.
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What Is Dough Hydration?
Dough hydration is the percentage of water in a dough relative to the amount of flour, calculated by weight, not volume.
The formula is simple:
(Water weight ÷ Flour weight) × 100 = Hydration percentage
Here is what that looks like in practice, based on 500g of flour:
500g flour + 300g water → 60% hydration
500g flour + 350g water → 70% hydration
500g flour + 400g water → 80% hydration
500g flour + 450g water → 90% hydration
Each 10% shift changes how the dough feels in your hands and what the final crumb looks like. That is how significant hydration is.
Always measure by weight. Cup measurements vary depending on how flour is packed, and that inconsistency will follow you all the way to the oven.
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Why Hydration Matters
Hydration affects everything from how your dough handles to the structure of the finished loaf.
60% hydration → Firm dough, easy to shape, tight even crumb. Ideal for sandwich loaves.
70% hydration → Softer, more extensible dough with a slightly open, tender crumb. The sweet spot for most beginner artisan loaves.
80% hydration → Sticky and slack. Requires stretch-and-fold handling rather than traditional kneading. Produces the lighter, more open crumb typical of rustic sourdough.
90% hydration → Very wet and fluid. Challenging to shape but rewards you with a beautifully open crumb. Common in ciabatta and high-hydration boules.
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Why the Same Hydration Can Feel Completely Different
Here is where things get interesting.
Not all flours absorb water the same way. A recipe that works perfectly at 70% hydration with bread flour can feel entirely different with whole wheat or all-purpose, even though the percentage is identical on paper.
Bread flour contains more protein and absorbs more water while still holding its structure. Swap it for all-purpose at the same hydration and expect a softer, looser dough.
Whole wheat flour absorbs significantly more water due to bran and fibre. A whole wheat dough at 70% can feel as firm as a white flour dough at 60%.
Rye flour is highly absorbent but does not form strong gluten, so the dough tends to feel dense and sticky regardless. Ancient grains like spelt and einkorn behave differently again and often need lower hydration and gentler handling.
Stone-ground flours retain more bran and germ, which increases absorption. More refined commercial flours may need less water to reach the same consistency.
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How to Adjust Hydration When Switching Flours
When working with a new flour, hold back 10 to 15% of your total water and add it gradually rather than all at once.
If a recipe calls for 500g flour and 350g water but you are switching to whole wheat, start with 320g water and adjust from there.
The signs are straightforward once you know what to look for.
Too dry: the dough feels stiff, cracks when stretched, or takes a long time to come together. Add water a tablespoon at a time.
Too wet: the dough is sticky, spreads uncontrollably, and lacks tension. Build strength through stretch and folds before reaching for more flour.
If your dough feels too wet right after mixing, let it rest for 15 to 30 minutes before making any changes. Some flours absorb water slowly, and what looks unworkable at the start will often tighten considerably on its own.
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Now, Let's Talk About the Math Behind It
Understanding hydration is one thing. Calculating it accurately every time you bake is another, and that is where baker's percentages come in.
Baker's percentages are simply a way of measuring every ingredient as a proportion of the flour. Flour is always 100%, and everything else, water, salt, starter, is a percentage of that flour weight.
Say you want to bake a sourdough loaf with 500g flour at 75% hydration, 2% salt, and 20% starter:
Water: 75% of 500g = 375g
Salt: 2% of 500g = 10g
Starter: 20% of 500g = 100g
That is it. No guessing, no estimating. Everything scales up or down from the flour weight, which is exactly why it works whether you are baking one loaf or ten.
The logic is the same for any bread. A classic sandwich loaf with 500g flour, 70% water, 2% salt, and 0.7% instant yeast gives you 350g water, 10g salt, and 3.5g yeast. One formula, any recipe.
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Accounting for the Flour and Water Inside Your Starter
One thing most beginners miss is that your starter is not just a leavening agent. It contains flour and water, and those need to be accounted for in your hydration calculation, or you will overshoot your target without realising it.
Here is how it works.
A 100% hydration starter is fed equal weights of flour and water. So 100g of starter contains 50g of flour and 50g of water.
Going back to the example above; 500g flour, 75% hydration, 20% starter:
Your starter contributes 50g of flour and 50g of water to the dough. This means your true flour total is not 500g, it is 550g. And your true water total is not 375g, it is 425g.
Your recipe hydration stays at 75%, but your true dough hydration, accounting for everything inside the starter, is actually:
425g ÷ 550g × 100 = 77.3%
That 2.3% difference might not sound like much, but at higher hydrations it compounds, and it is often the reason a dough feels wetter than the recipe suggests it should.
If you want to be precise, subtract the flour and water inside your starter from your recipe amounts before mixing:
Recipe water becomes 375g minus 50g = 325g
Recipe flour stays at 500g, but you are aware that 50g of it is coming from the starter
This way your dough hits exactly 75% hydration, not 77.3%.
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Where it gets harder is when you are adjusting hydration mid-recipe, switching flour blends, calculating what is inside your starter, or trying to scale a recipe to hit a specific dough weight. That is when the mental load adds up, and where small errors start compounding.
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In case you missed it, The Sourdough Playbook just launched.
Here's what The Sourdough Playbook Gives You
Everything covered in this post, hydration, baker's percentages, and how to account for your starter, is covered in depth inside The Sourdough Playbook, written in the same plain language you have come to expect here, with nothing assumed and nothing skipped. Every concept builds on the one before it, so by the time you reach your first bake, you are not guessing.
But understanding the theory is only part of it.
Every copy of The Sourdough Playbook comes with free access to the Baker's Math Calculator, both an online version that works on any device, and an offline Excel version you can use without internet. It is not a basic hydration calculator. It has nine dedicated tools covering flour blend selection with recommendations built in, true hydration accounting for what is inside your starter, starter feeding in both directions, reverse dough weight calculation, water temperature, hydration adjustment, recipe scaling, and banneton sizing.
You do not need to memorise a single formula. You choose your flour blend, enter your flour weight, and the calculator recommends your hydration, sets your starter percentage, and gives you the exact grams of every ingredient. The math is handled. You focus on the bread.
The posts on this page have always been free, and they always will be. But having it all in one place, structured, progressive, and paired with a tool that removes the mental load of the calculations, that is what The Sourdough Playbook bundle is.
You'll find the link in my bio and in the comments below.
As always, I hope it helps someone.
~ Neme's Kitchen
