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starter conversions

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msbreadbaker's picture
msbreadbaker

starter conversions

A question about figuring out the hydration level of an old starter recipe, please. If you had an old recipe with it's own starter and you wanted to use your own instead, how do I figure out what the recipe starter hydration is?


My existing starter is Peter Reinhart's original one from BBA and is about 7 months old. It works wonderfully, is 100% hydration. I have an old recipe I used to make from time to time and now want to use my own starter. I made it not too long ago using my present starter and it came out great. Then subsequent bakings, no so good. I attributed the change to not correctly adjusting the recipe for the lack of or too much of the liquid in my starter. But when I look at what the recipe originally calls for, it is more than I can figure out.


The recipe for the original starter: 3 1/2 cups unsifted strong bread type flour, 1 Tblspn sugar, 1 pkg dry yeast and 2 cups warm water. Beat until smooth, let stand in warm place for 2 days. (I refresh my present starter with high gluten flour, KA)


The bread part calls for 1 1/2 C starter, 3/4 C milk, 3 Tblspns sugar, 1 teaspn salt, 2 Tblspns margarine, 1/4 C warm water, 1 pkg dry yeast, 5-6 C unsifted flour.


I didn't get to use near the flour called for, it rose very well, even though I cut back on the yeast called for but it just wasn't right. Not light enough like the first time.


Any help would be greatly appreciated. Jean P. (VA)


 

Yumarma's picture
Yumarma

Your measurements round out about as follows:


3.5 cups flour = 125g X 3.5 = 125*3.5= 437.5g


2 cups water = 236g x 2 = 472g


Ergo your previous version is equal to 909 g of starter at about 109% hydration, not accounting for that 2 Tbs of sugar and a few grams of yeast.


You'd get an equivalent to that using 100% hydration starter with 874 grams of starter plus an extra 35 g of water.


After a quick search here, looks like Mike Avery reports that a cup of 100% hydration starter weighs in at about 280 grams, depending on how bubbly it is of course; we can assume it's been stirred and knocked down.


So from this, we can deduct that 1.5 cups would be just 420g, 46% of the quantity your recipe wanted you to build. Obvious as they started with 2 cups of water, already much more than what they needed in the recipe. I wonder what they wanted you to do with the remainder? A little more calculation and this means you'd want to use 404g of 100% starter plus an extra 14g of water.


Hopefully someone will check and make sure my numbers are right.


A side note on semantics, while we're here: for general purposes here on TFL, you'll find "starter" normaly refers to your standard wild yeast culture while what that recipe asked you to make falls more under the term "pre-ferment", usually a poolish, biga or pâte fermentée. 


Happy baking,
Paul 
Yumarama 


 

msbreadbaker's picture
msbreadbaker

Paul,


Thank you so much for your answer to my question regarding using one starter in place of another. When I first read your reply it seemed pretty complicated, but on 2nd reading, it was very clear. I printed it out and will use it as a reference when I make that bread again.


As to your wondering why the recipe called for so much in the way of ingredients for the starter portion, they wanted you to keep the remainder and treat it with replenishments and usings. Actually, even while this recipe did not use "weighing" the starter replenishment called for 1 1/2 C strong flour and only 1 C water, which would be about the amounts if you were weighing to get 100% hydration wouldn't it? No yeast in the replenishment. This recipe is very old and it was called "Sour Dough Starter", then Sour Dough Bread.


What makes the difference between the starter, poolish & biga? I've used all over the years, but in accordance with a given recipe, not giving any thought to if the terms were correct. Is it the use of commercial yeast?


Again, I appreciate you taking the time to figure this out for me, I would never have been able to do that on my own. Jean P. (VA)

Yumarma's picture
Yumarma


 Actually, even while this recipe did not use "weighing" the starter replenishment called for 1 1/2 C strong flour and only 1 C water, which would be about the amounts if you were weighing to get 100% hydration wouldn't it?



1.5 cups of flour, at about 125 g (4.5 oz, ok that's actually 127.5 grams to be more exact) per cup is then 190 g, while the cup of water is 236 g so it's more like 125%. This is allowing that the cup of flour accurately scooped which isn't always so; there can be great variances between scooped cups as you may well know, while weight is generally constant.


Although not an ironclad rule, you'll likely find that any pre-ferment (biga, poolish, pâte fermentée) noted in typical bread recipes will indeed be using commercial yeast. I say "not ironclad" because you can find recipes that make these with wild yeast sourdough.


Hope this helps,


Paul 
Yumarama