The Fresh Loaf

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substitution guide regular sourdough for dry?

apprentice's picture

substitution guide regular sourdough for dry?

Anybody have advice for me on substituting regular sourdough (mature culture at about 80% hydration) for dry sourdough culture? There's a barley bread formula I'd like to try that calls (in the home baker version) for 1/8 cup dry sour dough culture. By that, they mean the dehydrated product available at specialty food stores. Have never used the stuff, so I have no idea. Thanks!

dghdctr's picture

But any complete answer really needs more information.

Can you post a short version of the formula -- just ingredients and measurements -- to get us started?

My gut reaction would be to use enough live, active sourdough starter to replace maybe 25% of the total flour in the dough formula.  Take whatever water comes with using the sour starter and subtract that from the formula's total water.

As an example, if your formula called for 1000 grams of flour and 680 grams of water, we might use enough starter to "pre-ferment" or displace 250g of the flour (25% of 1000g).

To get 250g of pre-fermented flour from the starter, we'd also have to accept the 200g of water that comes with it (80% of 250g of flour is 200g of water, because of your 80% hydration rate in the starter).

So the adjusted formula would be:

  • Flour              750g (1000g minus the 250g in the starter we're using)
  • Water            480g (680g minus the 200g in the starter we're using)
  • Starter           450g (contains the 250g flour and 200g water)
  • Salt               Same as whatever you used before
  • Yeast            Same as before

Anything else in the original formula, like barley or whatever, would be added as before -- no changes made.  If the dough that results is too sticky, you can reduce the quantity of starter to 20% pre-fermented flour or even less, if necessary.

Hope that helps.

--Dan DiMuzio


apprentice's picture

Thanks, Dan! Really appreciate your having a look at this with me.

The formula was first prize winner in the Alberta Barley Commission's 2nd annual baking competition (2006). Anyone who's interested can find a larger and metric version of the formula at the Bakers Journal website. The home baker's version can be found at the ABC website. It's called Purple Barley Nut Bread.

Ingredients for the home baker's version are:

  • 1 cup rye flour
  • 2 3/4 cups bread flour
  • 1 cup barley flour
  • 1 T fresh yeast
  • 1/2 tsp salt
  • 1/8 cup dry sour dough culture
  • 1 3/4 cups water
  • 2 T chopped walnuts
  • 4 tsp sunflower seeds

The formula says to soak the walnuts and seeds at least 2 hours in room temperature water. There's no adjustment to the final dough water for what may have been absorbed during the soak.



apprentice's picture

Hi again, have had a closer look at the two formulas for this bread -- the larger one published in the Bakers Journal and the home baker's version from the Alberta Barley Commission that I included in previous post. Please don't waste your time on the latter. There is only a loose relationship between the two formulas. I think the student was probably in the early stages of learning how to scale formulas up and down -- or sideways? :)

She took a prize with the bread, though, and it fits in with my barley adventures. So I'm going to persevere. Will base my home baker's version not on hers (which I believe is out of balance, among other things on the yeast and the salt). Instead, I'll scale down the version published in BJ. I'm using that one because overall, the percentages are in balance. Have done rough calculations but need to double-check them.

Will post revised home baker's version in due course. Then perhaps you wouldn't mind revisiting the issue of how much mature sourdough I should substitute for the dry sourdough culture she lists as an ingredient?

Thanks again. Apprentice aka Carol

dghdctr's picture

You may have to alert me when you need a reply, but that would be fine.

--Dan DiMuzio