## An easy hydration calculation for sourdough bread.

What is hydration? Bakers refer to the flour weight as 100% and water is a percentage of the total flour. A common misconception is that this sum is a percentage of the dough. It is actually the percentage of all water compared to all the flour.

### The hardest bit is that you will need to do some maths first to put the right numbers in this calculator!

For the flour, **it is all the flour.** So add the flour in your starter/leaven + flour in the formula = TOTAL FLOUR

The water is the water in your starter/leaven + the water from the formula = TOTAL WATER

(This easy to do when your starter is 100% hydration. ie there is the same about of water as there is flour)

# For advanced bakers

This calculator is for advanced bakers, and is useful if you start using a stiff starter or a higher hydration starter.

For this reason, we have developed 2nd advanced 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).

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.

Martin says

I have a suspicion your 2nd calc is still incorrect. Maybe.

I’ve entered 500g flour, 380g water and 120g of starter.

Starter is 100% hydration (so 60g flour and 60g water.

All good except, ‘total flour’ field is showing 620g.

This isn’t possible if my starter only has 60g of flour.

If I’m right the Total Flour should be 560g? (Being 500g dough mix + 60g from starter)

Not sure if this skews your overall hydration calc or not.

Vanessa Kimbell says

Thanks Martin – we will keep looking at it.

Vanessa Kimbell says

Hello Martin, I have checked it again and the figures work for me – I get 560 using your figures. Always good to get feedback though so thank you for that.

Jacob Reach says

Hi, I don’t think the second calculator is fixed. It says my 150 grams of starter has 20 grams worth of water and 130 grams worth of flour at 60% hydration starter. It seems it only works if I enter in 100 grams worth of starter.

Vanessa Kimbell says

Thanks Jacob, we will go through it again and check.

Vanessa Kimbell says

Hello Jacob, I think it is fixed now!

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/

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.

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.