### Sourdough Hydration Calculator

What is hydration?

Bakers often talk about hydration as a percentage, which causes a common misconception. It is often assumed that the percentage is a percentage of the dough, but in actual fact it is the percentage of water compared to the amount of flour. For this reason bakers tend to refer to the flour weight as 100%.

Sometimes you might come across a recipe which gives values in percentages, and sometimes you might come across a recipe which gives a different hydration level of starter to yours, and need to work out how much more or less water you need to add.

For that reason we have developed two sourdough hydration calculators. The first one is a percentage calculator. Simply enter the total weight of flour (including any flour in your starter and/or leaven).

Then as you enter amounts for other ingredients such as salt and water the calculator will tell you the percentages. (Again don’t forget any water in your starter and/or leaven).

We’ll work through an example with my sourdough bread recipe here, and work through the values.

We add flour from the starter (assuming 100% hydration this will be 50g), plus the 500g of flour in the recipe.

We add the water from the starter and the water called for in the recipe, a total of 350g, and salt, 10g. We can now see that the hydration is 63.6%, and the salt percentage is 1.8%. If you then wanted to adjust this recipe to 66% you can adjust the water accordingly, and find you need 375g.

The second one is for converting recipes where a different hydration of starter is given to yours. Again we will use my sourdough bread recipe. This time we will assume that although the recipe uses starter at 100% hydration yours is actually 50%.

In this case we add the flour weight on its own, the water as given in the recipe, 300g and our starter, 100g. If we enter 50% hydration for the starter the calculator will work out for you that your total water is 325g, the total flour is 575g, and the hydration is 57%. We can now add water until we get to the required hydration of 63%, and see we need to adjust the recipe to add 339g of water.

R Purtcher-Wyde says

There seems to be an issue with the calculator, if you add ONLY starter (200g) and set a hydration of 100%, the “total flour” comes up at 175g and total water at 25g.

Vanessa Kimbell says

Hi Ralph, many thanks for pointing this out. I will get someone to fix this. Vx

Vanessa Kimbell says

The second calculator is now fixed! Thank you for pointing it out.

Donald Evans says

I’m struggling with your calculation of the flour and water content of your 50% hydration starter for the second calculator.

Surely 100 grams of 50% starter contains 67 grams of flour and 33 grams of water and not the 75/25 that you specify which is a 33% hydration

Please forgive me if I an wrong

Vanessa Kimbell says

Hi Donald and thank you for pointing this out. I will get someone to fix this. Vx

Vanessa Kimbell says

I think the second calculator is now fixed! Thank you for pointing it out.

Amir says

Hi

I need papers or references to know more about breads.

I love to bake bread at home

Sincerely

Amir

Chemist

Sarah Smith says

Hi Amir. We have a database of studies relating to sourdough, maybe some of the papers would be of interest to you. You can find it here – https://www.sourdough.co.uk/research/