Preferments and ripeness.
Biga, pâte fermentée, poolish, etc., preferments all.
All have different points at which they are considered "ripe" or most-suited for use in (usually) a final dough.
I'm having trouble understanding how this ripeness point is derived?
If you change the seed quantity (up or down) and temperature (up or down), the ripeness point comes sooner or later. Yes. So, is "ripe" a derivation of yeast quantity per mass? Or is it just some woo-woo empirical notion that says "When it looks like this, it's ideal!"). If not, how is it derived? Yeast growth curve?
Also, what of extended prefermentation? If the result of prefermentation is increased acidity, esters, and other organics, why be concerned with ripeness at all? Why not just let the preferment proceed until it can't ferment anymore? Too much acidity, which strengthens gluten, so we don't want to push acid development too far, else shaping, spring, and eating-quality issues? Or is the real concern with leavening: that excessive prefermentation exhausts food supply and, thus, yeast growth stops and begins to die and, thus, preferment gradually loses its capacity to leaven (even if it can still make delicious!).
[I ask this because I tend I tend to use preferments more for flavour enhancement, less for leavening (i.e. I'm perfectly happy to use a bit of commercial yeast in the final dough knowing that my preferment has done the work to extract flavour.) Thus, my thinking: If I were to stop using commercial yeast in final dough altogether (what some consider a crutch or inauthentic), I'd better learn something (pay more attention to) ripeness–and stop being comfortable with my preferment doing its thing for 16, 24, oops! 30 hours!]
(Sorry for the circular logic, if it can indeed be called logic. My brain is not a linear enterprise, so I'm fully comfortable asking stupid questions if the result makes me less so.)
it is kind of woo-woo empirical. The pre ferment should be at the point where it is fully expanded or slightly receding. This is where most bakers feel the taste and aroma are "optimal" - but there are other factors.
If it is a commercially yeasted pre ferment, or if you supplement a sourdough based pre ferment with commercial yeast in the final dough (as more than one well respected baker does) - the concern is not primarily the leavening power of the pre ferment. However, one does need to consider the percentage of flour that has been pre fermented and adjust for the fact that the starches/sugars in the pre fermented flour have been depleted and will no longer be available for any leavening (even that added in the final mix) to use. This will result in dull loaves with an unappealing crust and low volume.
You also forget one factor - the degradation in the gluten that can come from protease action. If I have a pre ferment that has gone on too long and the gluten is degraded too far, this will impact the aspect of my finished loaf. We generally use a poolish to enhance extensibility with our stronger flours. this is because the protease action occurs more rapidly in a liquid environment. Again, push this too long and the extensibility turns into (woo-woo term here) "flabbiness" and the dough will not perform properly.
With wheats (or other grains) that don't have the strength of the mid-western winter wheat, this is particularly important and we tend to use pate fermentee or a salted stiff levain to make sure that we get the flavor and the acids without too much degradation of the gluten.
My general impression is that the correct degree of ripenes is pretty important factor in the process. I know this for myself, because when I started with sourdough breads, I let the sourdough get consistently over-ripe. This produced a lot of bad looking loaves. Then I got taken in hand a taught how to judge ripeness - and well, things got significantly better.
Hope this helps.
The breads I've been making lately–breads with a lot of (often overripe) preferment–do have a certain "this loaf looks kinda' weird" quality (issues with oven spring and spreading). It's been bothering me a bit, but I chalked it up to the hand-mixing and/or not being too familiar with some of the flours I'm using.
My problem might actually be proteases and what they're doing to the gluten. Hrmmm!
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I'll probably have more questions later, but I need to re-read your comment.