June 10, 2020 - 10:30pm
Why would you build a levain differently from your starter?
The most obvious answer is to build up a different taste profile. But...
1. The levain is only a small portion of the total dough formula. Can you really tase the difference if you build it up from different flours?
2. My understanding is that feeding a starter a different flour mix than what it's "used to" can hinder its strength. This can adversely affect the bread, right?
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Hope this thread gets revived because I've been wondering these same things for forever.
Just for the sake of full disclosure, I have not yet managed to get a starter off the ground. But over the course of the last three weeks or so, I’ve been reading like crazy. The answer I’m giving here is just my best educated guess, based on the things I’ve read here and on other sourdough websites. If anything I have stated here is incorrect, I welcome feedback from more experienced bakers:
Once a sourdough starter has matured, and contains a stable mix of lactic acid producing bacteria and wild yeast cultures, a small amount of it should be able to successfully ferment any levain, regardless of what mixture of flours the levain is made of. The starter serves only to inoculate the levain with the microorganisms necessary for fermentation. While the strength of the starter (which is basically the measure of how much wild yeast is present) has an effect on how quickly the levain ferments, the fermentation of the levain does not serve to change the strength of the starter culture, as the fermentation phase of yeasts involve the production of waste gases (CO2), while the strength of the starter is developed during the reproductive phase. (Besides, even if your levain did hamper your yeast’s ability to reproduce, you’re getting ready to cook them anyway.)
Since every recipe seems to call for its levain to be comprised of ingredients specific to that recipe, it stands to reason that many different levains must be able to be produced from the same starter. Otherwise, one would need a different starter for each and every different type of bread they choose to make.
In regards to the other question, let me postulate this: the spices that go into pizza sauce make up a very small portion of the overall pizza recipe. But if you swapped them for the spices that go into a spaghetti sauce, don’t you think you’d be able to tell the difference when you ate a slice?
Thanks for responding. I am no expert either, but I can testify (as can almost any other baker) that feeding your starter a different flour mix will indeed reduce its strength. So for example, while your levain may be composed of 20g mature starter + 40g "other flours", your end result is still a weaker composition than if you were to feed it the same flours. Sure, you'll still get fermentation, and bread will come out. Maybe you can even make up for it by experimenting with bulk fermentation times. But my suspicion is you won't get the same result. Also, I actually haven't come across many recipes that call for a custom levain build, maybe aside from those on a certain popular sourdough blog that tends to overcomplicate things.
As for your spices example, I don't think you can equate the strong flavor profile of most spices to those of flour. A pinch of cumin can easily overcome an entire dish, whereas I'm willing to bet you won't be able to tell the difference between a loaf with 10% whole wheat vs 10% rye or any other flour for that matter (assuming the remaining 90% is the same).
Let's put it is way: how many knives do you have in your kitchen? All knives cut but not all knives cut the same way. A fillet knife can cut bread...but a bread knife is easier to use and cuts more cleanly.
That's the same reason some keep multiple levains. Any levain might work...but some might work better. Different flours (whole grains in particular) can create different flavor profiles or supercharge the rise. Perhaps the handling of the levain increases/decreases acidic development.
A lot of recipes call for a couple of specialized feedings before making the dough and it doesn't seem to be a problem. I wonder if levains that decrease in strength are because we just don't know how to handle that starter yet.