Bread is made with only a few ingredients, flour and water being the most fundamental of them. Understanding the ratio between them, also known as hydration (or dough or bread hydration) can tell you a great deal about what qualities to expect from your dough and your finished loaf. From home bakers to seasoned professionals, hydration is a topic that always generates questions, so below we’re answering some of the most common ones.
What does hydration even mean?
In breadmaking, hydration refers to the total quantity of moisture in a bread dough. We quantify it using a ratio found by dividing the total weight of water (or water-containing liquids such as milk, juice, tea, or even alcohol) by the total weight of flour in a given recipe. The ratio of the two numbers (water / flour), written as a percentage, mathematically expresses what is referred to as hydration. Bakers often refer to doughs like our Pan de Cristal (100%) as high hydration, or “slack,” whereas a firmer dough like our Easiest Loaf of Bread You’ll Ever Bake (63%) may be referred to as medium hydration, or “stiff.”
Hydration affects doughs at every step of the breadmaking process, from how we mix and develop strength to how we fold, shape, and even bake. If you understand hydration, you’ll bake better bread. (For some side reading, I highly recommend our piece on baker’s math for a deeper dive into how we calculate and describe bread doughs.)
Why should I care about hydration?
While we do need water to make bread (and even cookies, crackers, or cakes) we don’t necessarily need to know things like hydration percentage or how it affects doughs to make great bread. That said, understanding hydration and its role in baking can help improve the quality and consistency of your breadmaking while also giving clues about how a dough will perform.
Here’s an example. If I go to make a recipe with all-purpose flour and a hydration percentage in the 75% to 85% range, I know before even mixing the dough that it will likely be slack or sticky. And similarly, a recipe hydrated in the 55% to 65% range will likely feel firm or even stiff. This knowledge helps guide my approach to the recipe while also enabling me to compare recipes in an “apples to apples” fashion.
Bonnie Ohara, baker, author, and owner of Alchemy Bread in Modesto, California, emphasizes the value of understanding hydration: “Knowing hydration can be a context clue when communicating with other bakers about a recipe.” She explains that knowing hydration is a good starting point to deepen your understanding of how to handle tricky doughs or troubleshoot problems.
To take this a step further, if I know a dough is high hydration (let’s say 80% or higher, roughly), the dough will likely present as slack and sticky, possibly requiring some adjustments in how I handle it. And by the same token, a firm dough (in the low 60s for hydration) may require less folding or other handling during fermentation. The big takeaway here is that knowing hydration is like checking the weather before setting out for a road trip. It prepares you for the conditions ahead.
How do we calculate bread hydration?
Hydration is calculated by taking the weight of water or liquid in a recipe and dividing it by the weight of flour to get a percentage.
Let’s look at an example recipe:
Remember that hydration = water / flour. So in the recipe above, if water is 750g and flour is 1,000g, the total hydration of the dough is 750 / 1,000, or 75%.
Another example: If a recipe has the same weight of flour and water (let’s say 750g of each), then the hydration would be 100%.
(A useful additional resource here is the piece I wrote on baker’s math.)
What about sourdough bread hydration? Does the flour and water in my sourdough starter or other preferments count towards the total hydration of my recipe?
Yes. Hydration refers to the total quantity of water in the final dough. Both the flour and water amount in a sourdough preferment or sourdough culture should be considered when factoring hydration. Think of it like this: Everything that comprises the loaf you place in the oven should be considered as part of the loaf.
Let's look further.
Here are the ingredients for a sourdough “country-style” loaf. While this example is a little more daunting, just remember what I said above: Total quantity of water divided by total quantity of flour = total hydration.
All-purpose flour: 400g
Whole wheat flour: 50g
Rye flour: 50g
Sourdough preferment: 100g (consisting of 50g flour and 50g water)
Let’s add it up.
Water: 375g (in the final mix) + 50g (in the preferment) = 425g
Flour: 400g all-purpose + 50g whole wheat + 50g rye (all in the final mix) + 50g (in the preferment) = 550g
These numbers mean that this loaf has 77% hydration (425 / 550 = .77).
What is considered high hydration or low hydration?
High hydration refers to doughs that are often in excess of 80% hydration. In some cases, hydration may actually exceed 100% due to the thirsty needs of high protein or whole-grain flours (such as our bread flour or whole wheat). In those situations, the recipe has more water than flour. At the other end of the spectrum are doughs that fall around 60% hydration, which would be considered low hydration or “stiff.”
But what does hydration do?
The importance of water in our baked goods cannot be overstated: No water, no bread (or coffee cake, or cookies, or almost any other baked good). Water enables fermentation, hydrates starches and proteins, and positively impacts texture, flavor, crumb, and keeping qualities. So, the more insight we have into the hydration of our doughs, the more we can understand how to use it to our advantage and understand the recipe or breads we’re baking.
Which ingredients besides water count towards hydration?
There are no hard rules here. Beyond water I treat liquids such as milk, tea, coffee, beer, wine, juice, kombucha, or kvass as water in terms of hydration. While the quantity of solids or subcomponents (juice pulp, milk solids, fat, alcohol, etc.) do vary in each example, there's enough water to count them as hydration.
What about butter, eggs, fresh fruit, or other ingredients with significant water content?
While it’s true that these all contain water and have impacts on doughs, for bread we generally don’t consider them as part of the hydration percentage. We do think about the functional impacts, however. For example, in baker’s math terms, brioche dough is often 50% butter, 50% whole eggs, and 10% water or milk. While the hydration percentage looks extremely low — too low to even hydrate the flour, yeast, or sugar — the dough still works beautifully. Why? Because the eggs are roughly 75% water, and the butter also contains around 18% water.
What about different flours? Does hydration change when I switch from all-purpose to a whole-grain flour in bread?
The way hydration is calculated doesn’t change with flour types. So, 1,000 grams of flour and 750 grams of water will always be 75% hydration; it doesn’t matter if the flour is rye, whole wheat, buckwheat, or gluten-free.
However, whole-grain flours are “thirstier,” and doughs made with whole-grain flours typically require more water. As a result, a dough made with all-purpose flour and hydrated at 75% will feel significantly softer than an equally hydrated whole wheat dough.
Does anything other than flour count as flour when calculating hydration?
For flour percentages, the best practice is to only include the milled product of grains. While cocoa powder, dry milk powder, potato flour, freeze-dried fruit powders, and other ingredients do absorb water from the dough, we do not consider them as part of the flour percentage. But, as with water content in eggs, do always consider the impact of any ingredient on hydration.
Is higher hydration always better?
Recently, there's been a trend toward higher hydration doughs, with the perception that the higher the hydration, the more skilled the bake, prompting the question: Is wetter really better? The answer is ... “Maybe. Sometimes. Not always.” Each dough has its own sweet spot. I asked Judson Smith, the co-owner and head baker at Brimfield Bread Oven in Brimfield, Ohio, to list some positive attributes of slack doughs. His list was long. Wet or high-hydration doughs “promote better extensibility, better fermentation, moister crumb, and better keeping quality.” But he also noted that with wetter doughs come challenges. They take “more skill to handle and shape, require longer bakes, and often have thicker crusts.”
Further, he noted that with enriched doughs such as challah, higher hydration can really be a problem, producing “slumpy finished products and less strand definition.” Ultimately, low-hydration doughs can have great applications in baking. From loaves that look better with definition (as with braids), to bagels or pretzels, which have a more closed crumb structure and toothy chew, too much water can sometimes ruin the day.
Can I adjust hydration?
Yes! Hydration can be adjusted at any point. It’s something that professional bakers adjust in small degrees while mixing; we add a little water if a dough feels “thirsty” or hold some if necessary, depending on the season or flour composition. At home, I also make small adjustments when swapping whole-grain flour into a recipe or adapting to dry seasonal conditions on the fly.
But for any big, longstanding changes (in the case of water, let’s say a change bigger than 3% to 5%), I recommend working with baker’s math to calculate adjustments and ensure that ratios between ingredients remain intact. So, if a dough sits at 74% hydration and I consistently add what I calculate to be a full additional 3% of water, I’ll eventually make that change in my files, updating the formula to reflect the 77% hydration baguette that I like to make.
Are there any tips for dealing with high-hydration breads?
There is a learning curve with high-hydration doughs. It’s important to begin with breadmaking fundamentals, gaining experience folding doughs, maintaining leavens, shaping, scoring, and loading. Then as skills and confidence build, practice shaping gently, and folding for strength as I suggest in our hydration tips video. So, before you go to the 100% hydration Pan de Cristal (and the even wetter chocolate version), maybe you try our 80% hydration Pain de Campagne and get comfortable with the folding methods and dough handling.
We hope that these answers add some clarity to the hydration conversation. Armed with this information, you’re ready to take on everything from stiff pan loaves to softer hearth bakes. If you get tripped up, don’t forget our piece on baker’s math and tips videos to help you along the way. And we’ll keep engaged in our comments section, looking for ways we can support great bakes and beautiful loaves.
Cover photo by Mark Weinberg, food styling by Liz Neily.