The Fresh Loaf

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Converting from commercial yeast-based preferment to a levain/starter-based preferment

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hasunhats's picture
hasunhats

Converting from commercial yeast-based preferment to a levain/starter-based preferment

Hi,

First, I'd like to thank this community for being so helpful! This is my first post.

I have checked this forum and many other sites, read and re-read books and have tried to find a somewhat easily understood method or way of converting commercial yeast-based preferments (biga, sponge, poolish, etc.) to a levain/starter-based preferment? Most of what I see goes a little over my head so does anyone have any tips?

Thanks!

 

 

mwilson's picture
mwilson

You can't.

Yeast preferments and a levain (french style sourdough) are two different things...

I am wondering why you want to perform such a notion..?

Just start a levain naturally, it's not difficult and many here including myself will be happy to help you.

Michael

MangoChutney's picture
MangoChutney

If you mean how do you convert a recipe, that is possible.  I can't recall off the top of my head how much levain replaces how much dry yeast, but once you get that number then you remove from the rest of the recipe the flour and water that went into making that much levain.

 

mwilson's picture
mwilson

I think your interpretation of the question is the correct one. I should have re-read, although there is no mention of the word 'recipe'.

MangoChutney's picture
MangoChutney

No, there is no word "recipe" in there, but as you said the actual conversion isn't possible so it seemed unlikely to me that someone was getting confused by instructions on how to do that.  Whereas, some of the instructions published for converting from dry yeast to levain could get pretty hairy if you didn't understand hydration and baker's percentages.

hasunhats's picture
hasunhats

Yes, I mean in a formula or recipe that has an existing preferment made with commercial yeast, but I would like to create a levain or starter instead.

Thanks for the replies - my fault for not specifying.

MangoChutney's picture
MangoChutney

Well, this is how I bake one 9" x 5" loaf of whole grain bread.

I start with about one cup of starter, which I keep in the refrigerator in between baking sessions.  It's a nice, active, home-grown culture.  I'm going to assume that you are starting there, which you probably aren't, but eventually you would be there. 

To this starter I add 5 ounces of water and 8 ounces of whole grain flours.  This ferments overnight.

In the morning, I remove one cup of it and put that back into the refrigerator.

The rest of the loaf consists of 16 ounces of whole grain flours plus 8 ounces of water, 4 ounces of Greek yogurt, one teaspoon of salt, and one tablespoon of olive oil.  The flour, water, and yogurt soak overnight.  The salt is added at the beginning of the kneading, and the oil at the end of the kneading.

This bakes into a single two-and-a-half-pound loaf.  It seems to be nice bread, so I am guessing that one cup of active starter substitutes properly for one packet of dry yeast.  You'll have to adjust the flour and water in your preferment to account for that in the starter, but it seems to me that the water part is the more important.  You might even just try it as is, and adjust from there in later loaves, but I think it may be too wet.

Note:  All of these ounces are weight ounces, not volume ounces.

hasunhats's picture
hasunhats

My main question is say I want to take a recipe that calls for 200g of poolish. Can I sub the poolish with roughly the same amount of levain? Does doing this require another step? Or is that oversimplified?

Hopefully this helps target into my main area of confusion. I know I'll learn something!

MangoChutney's picture
MangoChutney

It sounds okay to me, if the levain is active.  That is, I am not sure that taking a cold starter out of the refrigerator and using that straight instead of poolish would work.  But certainly if you feed the starter and let it become active at room temperature, that should work.  That's essentially what I do.

Say that you have 50 grams of saved starter.  You add 100 grams of flour and 100 grams of water (or whatever ratio the poolish calls for).  You let that ferment for the same amount of time that the poolish was supposed to ferment, then put 50 grams away in storage.  What you have left is 200 grams.

hasunhats's picture
hasunhats

Will give it a try. My starters are very active so that's a good start. Thanks for the feedback!

wally's picture
wally

In my experience, you can treat this as a substitution generally, with qualifications.  The major one being this: if you're converting a biga to a levain, then you need to make sure your levain has the same proportions (flour/water) as your biga.  Same holds true with poolish. So, if your recipe calls for 100 gr of preferment, for example, you want to do a levain build that results in 100 gr of fermented dough.  This brings us to the minor qualification: whereas in most preferments (non-commercial) you only use a "pinch" of yeast, in the case of using levain as a build you have to measure/weigh.  I would suggest using an active starter that's about 20% of the total preferment based on a 12 hour ripening.

Keep in mind that substitution of levain for preferment may result in a slight flavor variance, but unless you live in the San Francisco area, it should not be that noticeable.

Larry

BHSS's picture
BHSS

I am new to this forum and a novice at using wild yeast starters and have been trying formulas from Reinhart's Whole Grain Breads.  I am interested in finding out whether any of his 'enriched bigas' (i.e. bigas that contain something besides flour, yeast, and water--his brioche biga, for example) can be modified to use wild yeast starter.  My reason is part curiosity, part desire to keep my wild yeast starter fresh by maximising its use.

This thread is the closest I have come to a discussion of the subject.  I am comfortable with the idea of replacing the commercial yeast with wild yeast starter but I am unsure of the math where other liquids are present in the biga.

For example, the formula for the whole wheat brioche biga in WGB is:

100% flour

.4% instant yeast

81% eggs (I am assuming that eggs are 75% water, so this is 60% hydration)

 

Here is what I think the formula would be for a wild yeast starter version:

flour 100%

eggs 47%

75% hydration wild yeast starter 33.3%

I took the 33.3% starter figure from the wild yeast starter formulae in WGB and am assuming it is an appropriate amount.  The starter contributes 25% hydration to the pre-dough, so to keep the hydration at 60%, I reduced the egg to 47% (35% hydration).

Does all the above seem sensible or am I missing something?  I am unsure if reducing the amount of eggs will change the bread for the worse.

Am I going about this the wrong way; should I be looking at simply moving the enrichments (eggs) to the final dough and substitute the 'standard' wild yeast starter given in WGB for the biga?