Percent Hydration?

I keep coming across N % hydration in various recipes... how do you calculate it? Thanks!
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Maedi's picture
Maedi 2009 December 6

Hi Acceber

I'm sure others will pitch in but according to Dom in his Sourdough Experiment #3:

Hydration refers to the proportion of water in a dough relative to the amount of flour. It is usually expressed in terms of percentage of total flour weight. To calculate hydration add up the weight of all of the liquids in the dough (including water in the starter), and divide by the total weight of flour in the recipe (including that in the starter). Multiply by 100 to get a percentage.

Might I add that the recipes section automatically calculates hydration and bakers percentages for you when you upload a recipe.


Hope that helps. All the best!

margaret simpson 2010 March 4

I'm a beginner at sourdough baking, but I've got a really good starter that bubbles up nicely and smells nice and kind of bready/yeasty, started from the dried started that Graham sent to me. I followed his instructions and feed 150g water & 150g flour to about 25g starter each day.

I've tried his recipe 4 times, and the Norwich Sourdough recipe from WildYeast, but it seems no matter what I try, I keep getting a very flat, dense loaf. It rises well during proving but just doesnt spring up in the oven, though I'm using a stone. I typically halve the quantities so I only make one loaf at a time. I'm in Sydney, its reasonably warm here.

I have two questions; firstly, hydration -- I saw you recommend the Pain de Campagne recipe as good for beginners, and I see that it requires 80% hydration starter.  Since my starter is always fed a 50:50 mix of flour/water, I gather my starter is at 50% hydration. And if that's the case, to convert to 80% hydration do I add 30g extra water to every 100g starter?

and secondly, should I be feeding the starter say 8 hours before I use it then ONLY using it only when its fully bubbling and risen? Does it matter what stage of the bubbling process I use it?



LeadDog's picture
LeadDog 2010 March 4

 The hydration question is easy to inform you on.  The hydration is the percent of water to the flour.  Your starter is 100% hydration since the water is equal to the amount of flour that you have.  To make a bread that is 80% hydration would be something like 800 grams of water and 1000 grams of flour.

Yes the starter should be feed 8 to 12 hours before you use it and use it when it is at its peak of activity.  It helps to use the starter at the peak of its activity since that is when most of the yeast are active.  Before the peak the yeast are multiplying and not as many of them.  After the peak they slowly start to die off.

rossnroller 2010 March 4

 Excellent advice from LeadDog. I'd just add that in warmer conditions, the starter is likely to peak closer to 8 hours than 12 after its last feed. In fact, in extreme temperatures such as those Perth has been experiencing in recent weeks (34-38C inside my kitchen), starters can peak after 4 hours. 

For a starter hydrated at 80-100%, it has peaked is when it is puffed up and domed on the surface, and not rising any further. If it starts to fall back a little, usually the first sign being a sinking in the middle of the dome, it's still OK to use, but you wouldn't want to wait much longer.


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