Hydration is the single most important number that describes your sourdough dough. It is expressed as a percentage and represents the ratio of the total water weight to the total flour weight in a recipe. A dough at 70% hydration contains 70 grams of water for every 100 grams of flour.
The concept comes from baker's percentage, a system where flour is always 100% and every other ingredient is stated relative to flour. Hydration is simply the baker's percentage of water. It is the first number an experienced baker looks at when reading a new recipe because it immediately tells you what the dough will feel like, how open the crumb will be, and how the crust will develop.
Understanding hydration is essential because the same flour, the same fermentation, and the same shaping technique will produce dramatically different loaves at different hydration levels. A 65% hydration dough makes a tight, sandwich-friendly crumb. An 80% dough makes an open, airy crumb with large irregular holes. Neither is better; they are different tools for different bread.
The basic formula is straightforward:
Hydration (%) = (Total Water / Total Flour) x 100
If your recipe calls for 500 g of flour and 350 g of water, your hydration is (350 / 500) x 100 = 70%.
Here is where most beginners make their first hydration mistake. Your sourdough starter is not just a flavoring agent; it is a mixture of flour and water. If you feed your starter at 1:1 (equal parts flour and water by weight), it is a 100% hydration starter. That means half of your starter is flour and half is water.
To calculate the effective hydration of your dough, you need to account for the flour and water contributed by the starter:
Worked example: A recipe calls for 450 g bread flour, 315 g water, 100 g starter (at 100% hydration), and 10 g salt.
If you only looked at the listed flour and water (450 g and 315 g), you would calculate 70% hydration and underestimate the true wetness of your dough. The sourdough calculator handles this math for you automatically, accounting for whatever starter hydration you use.
The table below is a reference for what to expect at each hydration level. These descriptions assume a standard white bread flour (around 11-13% protein). Whole grain flours will feel drier at the same hydration because they absorb more water.
| Hydration | Dough Feel | Difficulty | Crumb Style | Best Uses |
|---|---|---|---|---|
| 60-65% | Stiff and smooth. Holds its shape on the counter without spreading. Easy to handle and shape. Feels like modeling clay. | Beginner | Tight, uniform crumb with small, evenly distributed holes. Dense but not heavy. | Bagels, pretzels, sandwich loaves, rolls, enriched breads. Any bread where you want a consistent, sliceable crumb. |
| 65-70% | Smooth and slightly tacky. Pulls away from the bowl cleanly. Easy to shape with minimal sticking. | Beginner | Even crumb with small to medium holes. Good structure with a slight openness. | Classic sourdough boules, batards, everyday table bread, pan loaves. The sweet spot for beginners. |
| 70-75% | Tacky but manageable. Sticks slightly to your hands. Requires a light touch and wet hands during shaping. Moderate spread on the counter. | Intermediate | Open crumb with a mix of small and medium holes. Slightly irregular, airy texture. | Artisan sourdough loaves, country bread, rustic boules. The most popular range for home sourdough bakers. |
| 75-82% | Wet and sticky. Clings to hands and surfaces. Requires confident handling, bench scrapers, and well-floured surfaces. The dough spreads noticeably. | Intermediate | Open, irregular crumb with large holes. Light, airy texture with a glossy interior. | High-hydration artisan loaves, ciabatta-style bread, open-crumb boules. Great ear and oven spring when shaped well. |
| 82-90% | Very wet and slack. Feels almost like a thick batter at times. Requires stretch-and-fold or coil-fold techniques rather than traditional kneading. | Advanced | Very open crumb with large, irregular holes. Thin, translucent cell walls. Custardy texture. | High-hydration artisan loaves, ciabatta, focaccia, pan-baked breads. Spectacular when executed well but unforgiving of mistakes. |
| 90%+ | Extremely wet, almost pourable. Cannot be shaped freestanding; must be baked in a pan or on a sheet. Requires extensive folding to build any structure. | Expert | Extremely open, lacy crumb. Large, irregular caverns throughout. Very thin cell walls. | Focaccia, ciabatta, experimental loaves, pan breads. Often baked in a pan to contain the spread. |
Not all flours absorb water equally. The protein content, bran content, and particle size of your flour all affect how much water it can hold. This means the same hydration percentage will feel very different depending on what flour you use.
Bread flour is the standard reference point for hydration discussions. Its moderate protein content forms a strong gluten network that can hold water effectively. A 75% hydration dough with bread flour will be tacky but manageable. Most hydration recommendations you see online assume bread flour unless stated otherwise.
All-purpose flour has less protein and therefore less water-absorbing capacity. If you substitute AP flour into a recipe designed for bread flour, the dough will feel wetter than expected. Consider reducing hydration by 2-5% when using AP flour. A recipe that calls for 75% hydration with bread flour might feel better at 70-73% with AP flour.
Whole wheat flour contains the bran and germ, which act like tiny sponges that absorb water aggressively. A 70% hydration whole wheat dough can feel as stiff as a 60% white flour dough. When using whole wheat, increase hydration by 5-10% compared to what you would use for white flour. Many whole wheat sourdough recipes run 78-85% hydration to achieve a workable dough.
An important technique with whole wheat flour is the autolyse: mixing just the flour and water and letting it rest for 30-60 minutes before adding the starter and salt. This gives the bran time to fully absorb water, making the dough smoother and easier to work with.
Rye flour absorbs even more water than whole wheat, but it behaves completely differently. Rye contains very little gluten-forming protein. Instead, it relies on pentosans (a type of carbohydrate) to hold its structure. At high percentages of rye (above 50% of total flour), the dough will feel sticky and paste-like regardless of hydration. For 100% rye breads, hydrations of 80-90% are common, and the dough is more like a thick batter than a shapeable dough.
Spelt contains gluten but forms a weaker network than wheat. It also absorbs water faster but holds it less tightly, so spelt doughs tend to feel wetter than their hydration suggests and can become slack during long fermentation. Reduce hydration by 5-8% compared to bread flour, and shorten bulk fermentation slightly.
| Flour Type | Protein Range | Water Absorption | Hydration Adjustment | Notes |
|---|---|---|---|---|
| Bread flour | 11-13% | Moderate | Baseline (no adjustment) | Standard reference for most recipes |
| All-purpose | 9-11% | Low-moderate | Reduce 2-5% | Weaker gluten; dough feels wetter |
| Whole wheat | 12-14% | High | Increase 5-10% | Bran absorbs water; use autolyse |
| Rye | 7-10% | Very high | Increase 10-15% | No gluten network; sticky by nature |
| Spelt | 11-14% | Low-moderate | Reduce 5-8% | Weak gluten; breaks down with time |
| Tipo 00 | 11-13% | Low | Reduce 3-5% | Very finely milled; absorbs slowly |
| Einkorn | 12-15% | Low | Reduce 5-10% | Very weak gluten; treat gently |
Your kitchen environment has a meaningful impact on how your dough feels and behaves. The same recipe can produce different results in summer versus winter, or in a dry climate versus a humid one. Experienced bakers learn to adjust hydration based on conditions rather than following a recipe rigidly.
In summer, flour absorbs moisture from the air over time. If your flour has been sitting in a humid kitchen, it already contains more water than its label suggests. The result: your dough will feel wetter than expected at the same hydration.
In winter, indoor heating dries out the air and your flour. The flour will absorb more water from the dough, making everything feel stiffer and drier.
At high altitude (above 1,500 m / 5,000 ft), the lower air pressure causes water to evaporate faster from your dough during fermentation and baking. Increase hydration by 2-5% and consider shortening your bake time slightly to compensate.
These are the most frequent errors bakers make when working with hydration, especially when moving beyond beginner recipes.
The most common mistake with high-hydration doughs is dumping all the water in at the start. Instead, hold back 10-15% of the total water and add it in stages. This technique, called bassinage, lets you build gluten strength first and then gradually incorporate the remaining water. The dough will be easier to handle and develop better structure.
As discussed above, your starter's hydration changes the effective hydration of your dough. If you switch from a 100% hydration starter to a 75% stiff starter without adjusting the recipe water, your dough will be drier than intended. Always account for the flour and water in your starter.
Saying "I made a 78% hydration loaf" is only meaningful if you also specify the flour. A 78% dough with strong bread flour and a 78% dough with whole wheat are completely different animals. When sharing recipes or following online tutorials, always note the flour type.
Social media rewards dramatic open crumbs, which encourages beginners to jump to 80%+ hydration before they have mastered the fundamentals. High-hydration doughs are unforgiving. If your shaping, folding technique, and fermentation timing are not solid, a high-hydration dough will spread into a flat disc. Master 68-72% first. Once you can consistently produce a well-shaped loaf with good oven spring at that range, increase hydration by 2-3% at a time.
Warm water makes dough feel slacker and stickier. Cold water makes it feel tighter. If you switch from cold water to warm water without changing the amount, the dough will behave as if the hydration increased. Use a desired dough temperature (DDT) approach, typically targeting 24-26C (75-78F), and calculate your water temperature based on the flour temperature and room temperature.
Hydration only works with weight measurements. A "cup" of flour can vary by 30% in weight depending on how you scoop it. If you are not using a kitchen scale accurate to 1 gram, no hydration calculation will be meaningful. Invest in a digital scale; it is the single most important piece of baking equipment.
If you have a recipe you like but want to adjust the hydration, here is the process. Let us say you have a recipe at 70% hydration and you want to move it to 75%.
Add up all the flour in the recipe, including the flour in your starter. Using our earlier example: 450 g recipe flour + 50 g flour in starter = 500 g total flour.
Multiply total flour by the new hydration: 500 x 0.75 = 375 g total water.
Subtract the water contributed by your starter: 375 - 50 = 325 g recipe water.
Change the recipe water from the original amount (315 g) to the new amount (325 g). That is it. You have increased hydration from 73% to 75% by adding just 10 g of water. Small changes in hydration make a noticeable difference in the dough.
The sourdough calculator does this math instantly. Enter your desired hydration, your flour weight, and your starter details, and it will give you exact ingredient amounts. You can learn more about how this math system works in the baker's percentage guide.
As you increase hydration, you need to adjust your technique at almost every stage of the process.
Low-hydration doughs (60-68%) can be kneaded on the counter like traditional bread dough. Medium-hydration doughs (68-75%) benefit from stretch-and-fold or slap-and-fold techniques in the bowl. High-hydration doughs (75%+) are almost always developed using stretch-and-fold or coil-fold sets during bulk fermentation rather than upfront kneading.
Higher-hydration doughs ferment slightly faster because the yeast and bacteria in your starter can move through the dough more easily. Watch the dough, not the clock. Look for a 50-75% increase in volume, a domed top, visible bubbles on the surface and sides, and a jiggly, airy texture when you tilt the bowl.
This is where hydration differences are most obvious. Low-hydration doughs are forgiving; you can handle them aggressively. High-hydration doughs require a fast, decisive touch. Use a bench scraper, keep your hands lightly wet (not floured, which will create a dry layer that tears), and practice tension-building techniques like the "envelope fold" and "drag toward you" method for boules.
High-hydration doughs score best when they are very cold. A cold retard in the refrigerator (4-16 hours) firms up the dough and makes scoring dramatically easier. Use a razor blade or lame held at a 30-45 degree angle for the best ear development.
Higher-hydration doughs produce more steam during baking (because they contain more water), which helps develop a crispy, blistered crust. They also tend to have better oven spring because the steam keeps the crust flexible longer, allowing the dough to expand before the crust sets. Bake in a preheated Dutch oven for the best results with any hydration level.
| Your Goal | Recommended Hydration | Notes |
|---|---|---|
| Tight crumb for sandwiches | 62-68% | Easy to shape, slices cleanly |
| Classic sourdough boule | 68-72% | Best starting point for beginners |
| Open, artisan-style crumb | 73-78% | Requires good shaping technique |
| Ciabatta or focaccia | 80-90% | Pan-baked; minimal shaping |
| 100% whole wheat loaf | 75-85% | Bran needs the extra water |
| Rye bread (50%+ rye) | 80-90% | Batter-like consistency is normal |
| Enriched dough (with butter/eggs) | 55-65% | Fat replaces some of the water's role |
Hydration is not a number to fear or obsess over. It is a tool. Once you understand what each percentage range feels like and how flour type and environment affect the dough, you can confidently adapt any recipe to your conditions and your goals.
Start at 68-70% hydration with a strong bread flour. Master shaping and fermentation timing at that level. Then increase by 2-3% at a time, observing how the dough changes. Within a few bakes, you will develop an intuitive sense of when the dough needs more water, less water, or a different handling technique.
Use the sourdough calculator to set your target hydration and get exact ingredient weights. Read the baker's percentage guide to understand the math system behind the numbers, and check the starter hydration guide to make sure your starter is not throwing off your calculations.
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