April 2, 2021

While beginning your sourdough baking journey, you may have come across the term ‘sourdough hydration’.

Don’t panic! You don’t need to be pouring bottles of water over your sourdough to quench its thirst and there are no fancy maths equations involved...just a few simple calculations. Honestly though, unless you’re super serious about sourdough baking, you probably don’t need to worry about calculating hydration levels (as long as you follow a brilliant sourdough guide like this one).

Nevertheless, once you understand this concept and know how to adapt your sourdough hydration accordingly, you’ll be able to bake bread that’s next level good!

In this article, we’ll outline:

  • The importance of hydration
  • The basic calculations you’ll need
  • How you can use these to change the texture, crumb, and crust of your bread
  • How to find the perfect sourdough hydration percentage for you
  • And advice on other factors that might affect the hydration of your sourdough

first, what does ‘sourdough hydration’ mean?

Put simply, it refers to how much water is in your sourdough.

However, a common misconception is that hydration refers to the percentage of the dough that is water, when in fact, it is actually the percentage of water compared to the amount of flour. This is because of what’s known as the baker’s percentage.

Ok, we’ll try to elaborate...

In order to help bakers scale-up production, someone came up with the concept of the baker’s percentage. What this means is that all ingredients are compared to the amount of flour used in a recipe.

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For example, let’s say a recipe calls for 100g of flour; this is your 100%. Everything else is compared to that quantity.

So, if the recipe requires 75g of water, that’s 75% of 100g of flour. The 75% is the baker’s percentage of water needed in this recipe.

2.2g of salt? A baker’s percentage of 2.2%.

20g of leaven (an off-shoot from your sourdough starter)? A baker’s percentage of 20%.

Got it?

This means that you can easily scale recipes up and down depending on how much flour you have or how many loaves you want to make. It’s also really helpful if you want to compare recipes to understand why they turn out differently.

But what’s the baker’s percentage got to do with sourdough hydration?

Well, the hydration is essentially the baker’s percentage of water needed to make your sourdough.

Great, now we’ve got that covered, you’ll probably want to know...

how do i calculate sourdough hydration?

*Hint* we’ve just shown you

The simplest calculation to work out your sourdough hydration is as follows:

(Water (g) / Flour (g)) x 100 = Hydration Percentage

Make sure to take into account the amount of flour and water used in your leaven as well. For example, if you use half flour and half water in your sourdough starter, then a 100g leaven would contain 50g flour and 50g of water.

Let’s take the following basic recipe:

300g water

100g sourdough leaven

500g of flour

10g fine sea salt mixed with 15g of cold water

The calculation would be as follows:

((300 + 15 + 50) / (500 + 50)) x 100 = 66% hydration

how to use the calculation to work backwards

The amazing thing about sourdough is that the 3 simple ingredients make it a relatively simple recipe to experiment with changing the hydration level.

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Let’s say that you know how much flour you usually use to make 1 loaf but you have decided to aim towards a 75% hydration percentage instead of the 65% you’ve baked before. You can simply adapt the above equation to calculate how much water to use in your new recipe.

Here’s what to do:

(Hydration Percentage / 100) x Flour (g) = Water (g)

If you’re using 500g of flour for a single loaf and you’re aiming for 75% hydration, your calculation will be as follows:

(75 / 100) x 500g of flour = 375g of water

Easy peasy, sourdough breezy!

why is sourdough hydration important?

Good question. For a number of reasons; sourdough hydration has an effect on shaping, oven spring, texture, crumb, and crust.

The higher the hydration percentage, the more easily ingredients are dispersed and the faster the rate of fermentation (make sure you don’t overproof though). This will mean that kneading is less important and sometimes not even necessary.

Click here to learn about the benefits of fermented foods

Of course, the dough will also become harder to handle, as the higher levels of water will make it sticky and slack. Extra steps can be taken to improve the strength of the dough, helping it to rise.

Make sure you keep an eye on our Sourdough Guide for more sourdough support and troubleshooting

what is the perfect hydration level and what will happen if i change it?

Bakers usually experiment with sourdough hydration levels between 65-90% but the percentage that is best for you depends on factors such as your experience level, the ingredients you use, and climate (e.g. humidity, temperature, and altitude).

Beginners may want to start with lower hydration levels since the dough is easier to handle. This will generally be easier to shape, will ferment more slowly, and provide a better oven spring.

More advanced bakers may want to experiment with higher hydration percentages to produce sourdough with a thinner crust and a more open crumb.

can factors other than water affect sourdough hydration?

Yes. Humidity, altitude, temperature, the type of flour, the hydration of your leaven, and other factors can all affect sourdough hydration.

For example, whole grain flours absorb more water than white flour, so you may want to increase your hydration percentage accordingly.

Click here to learn which flour to use for sourdough

The best suggestion we have is to experiment; don’t worry if you make mistakes and learn as you go along. Start with more white flour than whole-grain and aim for lower hydration levels, then work your way up. Keep a notebook in the kitchen while you bake so you can write down what went well and what didn’t.

And the most important thing? Have fun!