The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Starter - how to change the hydration level?

DianaM's picture

Starter - how to change the hydration level?

Dear fellow bakers,

I started out with a KA starter.  I am feeding 1 cup of starter 4 oz of water and 4 oz of flour once a day.  The starter is very active.  By dividing the 4 oz of flour into the 4 oz of water, I conclude that my starter is at 100%.  If this is not the case, please enlighten me, and then further enlighten me how to convert my current starter to various hydration levels given in bread recipes.  For one thing, I'm stuck on how much starter to use in the equation. The KA customer service rep said it didn't make any difference, but that doesn't seem logical to me.

I am SO looking forward to your replies,



cranbo's picture


Yes, your starter is at 100% hydration. 

To convert your starter to different hydration, just create a separate starter at the hydration and amount you need.

For example, if you need a 60% hydration starter and your recipe requires 340g of starter, then start with 200g of flour, 120g of water, and mix in about  20g of your liquid starter. Continue to feed your new starter at the new hydration ratio at least twice, and you're all set. 

You can also use the formula 

Fg + (SH% * Fg) = SRg


  • Fg = flour weight in grams
  • SH% is starter hydration percentage (such as .60 for 60% starter hydration)
  • SRg = starter amount required by recipe in grams

to determine the exact flour and water amounts required for a given starter amount. 

There are a few calculators that people have posted that can do the math for you, if you like. 

Does that help? 


DianaM's picture

Thank you for the quick response.

It is now 2:46 AM here and I'll need to study your reply with a clear head after a bit of sleep.



dmsnyder's picture

Cranbo's formula does not address the question of converting the hydration level of a starter to another hydration level. If you really want the starter you use to be a precise hydration, the following link walks you through the method:

Converting starter hydrations: A Tutorial. Or through thick and thin and vice versa

I hope this helps.


DianaM's picture


Thank you for the quick response.

It is now 2:46 AM here and I'll need to study your reply with a clear head after a bit of sleep. I did click through the links and it is apparent that I need to spend some time digesting the information provided.  Certainly, the responses contain exactly the kind of information I have been looking for. 

I'm fairly to to SD and my breads have been turning out quite nicely; however,  I've been hesitant to try to recipes when I switch cookbooks because I haven't clearly understoon how to change starter hydration.

Good night to all,



Mini Oven's picture
Mini Oven

Is a good way to reduce the power of your starter unless your temperatures are very cool.  The starter should be fed equal or more amounts of food... 8oz starter being fed 4 oz of flour is a starvation diet for a 24hr period at 73°F.

If you find your starter loosing power to raise loaves, reduce the amount of starter by half or better yet, by a quarter to 2 oz starter to 4oz water & 4 oz flour.

placebo's picture

Say you want a 125%-hydration starter. Start with 100 grams of 100%-hydration starter. That means it contains 50 grams of flour and 50 grams of water. If you were to feed it 50 grams of flour, you'd now have a total of 100 grams of flour. To get to 125% hydration, you would need 125 grams of water total. Since you already have 50 grams of water from the original starter, you need to add 75 grams. Voila! 225 grams of 125% starter. From then on, feed it using 5:4 water-to-flour ratio.

Want more or less starter? Say you want only 100 grams of starter at the end. Cut all the amounts in half: Start with 50 grams of starter and add 25 grams of flour and 37.5 grams of water. You'll have 112.5 grams of starter, and if you really want to, you could discard the extra 12.5 grams.

Many people here will say adding so little flour (compared to the amount of starter you begin with) is starving the starter. (Personally, I don't find this to be the case when feeding twice a day.) If you want to provide more food, start with less starter, say 60 grams. This time, you're beginning with 30 grams each of flour and water. Feed it 70 grams of flour to again get to 100 grams of flour in total, and add 95 grams of water to get 125 grams of water total. Again, you can scale all the numbers to get the amount you want at the end.