March 5, 2020 - 6:17pm
Why do some recipes call for BOTH starter/levain & instant yeast? Why NOT just levain?
Hi,
I'm working on my 5th iteration of Ken Forkish's "Field Blend #2" loaf, from his 'Flour Water Salt Yeast' tome.
To date, it's been follow-the-recipe, and work for consistency.
That's, now, pretty good. Now, I'd like to better understand, & potentially tweak, some of the bits ...
Atm, it's a question about the 'Final Dough' ... which calls for both
360g mature levain
AND
2g instant yeast
IIUC, from what I've been reading, one cup of sourdough starter is roughly equivalent to the rising potential of one packet of commercial yeast ... depending on activity etc.
So my *general* question is -- why are BOTH being used here? Why not just increase the levain?
I'm assuming there's a _reason_ ... I just haven't found a clear statement of it.
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If I recall correctly, Peter Reinhart explains this phenomenon in BBA. Put simply, the inclusion of a small amount of commercial yeast makes the rise more predictable. It takes up slack in the event your starter is not quite as vigorous as it needs to be.
You get the flavor of the sourdough and the more predictable rising times of a bread made with commercial yeast.
Somebody else please chime in here if I’m wrong.
If your starter is performing well just don't add the IDY, you don't even need to use more levain.
> f I recall correctly, Peter Reinhart explains this phenomenon in BBA
Well, then I've managed to miss it! Will look again ...
> If your starter is performing well just don't add the IDY, you don't even need to use more levain.
I keep my starter fed with 100% pumpernickel flour. It's been great -- always wonderful rises. I think I may simply omit the IDY as a 1st, next experiment.
Now off to to re-read ...
Thx agn 4 the comments!
pgs 234-235 of original edition printed copy BBA, in the grace note, mention combining commercial yeast with sourdough.
In the Kindle version of 15th anniversary edition BBA, same grace note, locations 6546 and 6566.
Adding yeast allows to control sourness, which many people don't like all that much. It also allows ligher, drier crumb, which many people prefer to more rubbery crumb of sourdough.
I agree with the above, another point is that commercial yeast also makes the time to bake after the preferment and yeast are added much shorter (around 3* rather than around 6 hours - if you start early, you can have a loaf ready for lunch, in fact I have just done exactly that with the Weekend Bakery pain rustique). Even if you could persuade your sourdough yeasts to get going in that time, it would not be ideal because there would not have been enough time to develop the dough. But the ravenous commercial yeasts will gorge themselves on carbs and produce gas at a sufficient rate to inflate even limp dough.
That Weekend Bakery recipe contains a higher proportion of prefermented flour (51%) than would be normal in a pure sourdough loaf. This would be necessary if the sourdough is to contribute anything to the flavour. Sourdough yeasts are not going to have done much by the time the commercial yeast has done its rising, so the flavours they contribute will mainly have been there as a result of the pre-ferment rather than the bulk ferment. By contrast, with pure sourdough, sourdough flavours will develop during the bulk ferment if you let them (eg by proofing in the fridge overnight). Or to put it another way, in a hybrid loaf you will develop your preferment with a view to the flavour you want in it rather than to developing a strong culture for the bulk ferment. Which I suppose illustrates the point about "more control".
*I guess you could add a carefully judged tiny amount of commercial yeast so that it kicked in at the same time as the sourdough, but that might be tricky to judge.