Reading some posts, people talk about hydration in percentages. How do you calculate that?

In my recipe, I use 350g wholemeal flour, 1 mug full (about 2 cups) of starter, 500ml of water for the sponge. I leave it for a day, then add a splash of oil, teaspoon of salt, 200g of white flour, 300g of wholemeal, dash of fennel seeds. I then knead it for 5 to 10 mins and leave it over night. The next day I knock it and proof it for up to 4 hours, slash it and finally pop it in oven for 15 mins on 250C, then 20 mins on 200C. I put a tray of water below the bread in the oven.

the result is great, though the bubbles are not large - not sure but suspects this is due to wholemeal flour. the bread also remains fresh for several days. what is my hydration percentage? am always looking to improve, so would love any suggestions.





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shasta's picture
shasta 2012 July 5

Hello Oliver,


I'll take a stab at this one; hydration is the total amount of water added, usually by weight divided by the total amount of flour by weight.


In your example you add a total flour weight of 850 g and a total water weight of 500 g.


500/850=.588 or 58.8% hydration. I think I have that right.


Now, some, including myself, also add in the starter to the equation. To do that, you will need to know the hydration of your starter and how much by weight you add. In your example above, I took some liberties and assumed the following:


Starter is 100% hydration, meaning that it contains equal portions of water and flour by weight

2 cups = 454 g or 227 g water & 227 g of flour.


If you add the weight of the water to the total weight of water in your recipe you get a new total of 727 g. If you do the same to the flour you get 1077 g of flour.


727/1077= .675 or 67.5% hydration.

As far as I know, the above is correct based on my assumptions.

I hope I helped.

Mr_Punchy's picture
Mr_Punchy 2012 July 6

Hey again Olivier,

Shasta is correct with her estimations, but to explain it in detail, in baking we use what are known as "Baker's Percentages" and they are confusing because they are not an "actual" percentage.

Baker's percentages measure every ingredient in it's relation to the flour weight.  For example, if you are making a loaf like this:

Flour 1kg

Starter 350g

Water 700g

Salt 18g


then the percentage hydration would be 70% because it is 70% of the weight of the flour.  (Does that make sense?)  There is a great sourdugh calculator on the "tools" page of this forum that you can use too.  I use one at home and keep a record of all of my bakes.  If you have trouble finding it, then I am happy to email you a copy of the one I use.  

The good thing about the % calculator is that you actually key in:

the number of loaves you want

the dough weight you want

the % wholemeal/rye

the dough hydration

the % starter

the starter hydration % (if it's 1:1 it's 100%)

the % salt

and the calculator spits out the recipe.  


I'd also like to suggest you use gram weights for all your measurements, including flour, water, salt and starter.  That way you know each recipe is acurate and you can tweak it more easily from batch to batch.  For instance, now it is winter, I have increased my starter % to counter the colder weather.  All I had to do on the calculator was key in a higher amount in the "starter %" box.  easy peasy.  

Anyway, hope that helps.  If you'd like the calculator emailed to you, send me a message w your email address.


Mr P


Olivier 2012 July 6

Cheers Mr Punchy! that's really clear.

how do you calculate the amount of salt so accurately, and is it so important to get it to the gram? apart from nicking an electronic scale from my place of work, I can't see how to get it right. Is a teaspoon or two ok? it seems like that sort of weight....




Mr_Punchy's picture
Mr_Punchy 2012 July 6

I find getting the ingredients accurate is a huge help, especially salt.  As salt is a preservative of sorts, it inhibits the yeast growth, so if you have too much, it will retard the development of your loaf.  It's strongly advised to weigh everything using digital scales.  I bought mine from the Good Guys for $30 and they are great. 


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