Stronger flour, weaker bread.

Please elaborate on this.

... could you elaborate on this?  I'm more or less a newbie but I've gotten a pretty fair amount of loaves on the belt.  I find that as I try different flours and mixtures, strange and surprising things happen to the dough that I just don't anticipate.  Lately I've been only using my home sourdough starter, because it is so delicious, seems natural to me, and rises all my breads easily (certainly cheaper than yeast).  What happens to the dough if the preferment over-ripens?  And just to clarify, we're talking about the "sponge" or the starter-batter, when we say-- "preferment?"

I've read several times that longer fermenting of the sponge increases the sourdough flavor.  Of course temperature and percentage of mother is relative, but how to be sure I'm not waiting too long?  I notice that after the plume of bubbles finishes collected on the center top of the sponge, and it has fully risen, it does not change after that, even after an hour or two and likewise after mixing again.  May I be correct in assuming this means it is more than ripe?  There have been instances where the dough, AFTER autolysing, slapping/stretch-folding, etc., becomes suddenly floppy and hyper-elastic, swinging wildly in any direction it can, stretching infinitely and refusing to be handled reasonably by any technique, slopping in bowls or on the counter, and grabbing anything and everything it can manage to reach like a monster, without ever letting go.  This is not usually my experience with wet doughs, but I think it might be related to the sponge.

it's a mystery, then.  I don't know if you can get the ash content of your two flours.  A higher ash content would indicate that the gluten is of lower quality (as it would mean the flour contained grain milled closer to the bran) even though the protein content is higher.

Good luck with your problem...

and or tweaking your starter to get the flavor back. Your room temperature (21C) will favor a nice sourdough. Crudely, for every +10C change in temperature the activities of the yeast & bacteria double within their optimal range (about 55-85F); a 5C change in temperature is significant.  Followed by shape, into the banneton, proof at room temp for 30-60 min (optional, your call), and then retard in the fridge overnight for 8+ hours. Take it out of the fridge and bake when it has nearly doubled in size from when it went into the banneton. If you skipped the optional proof, then you might have to give it some time after coming out of the fridge. If you proofed it substantially before retarding, you can go right into the oven after the retard if the size is right & the poke test ok. Scoring will be easier when the dough is cold, too. If you cannot roughly doubled it between your retard and post fridge warm up, you have overproofed your dough between the two processes.

My mantra is "if one is going to cock up the proof, better to underproof it than overproof."

Lots of flour, cornmeal or my personal favorite, rice flour, on the banneton will take care the sticking.

Can you quantify what you mean by "same thing but to a lesser extent?" A pictures is worth a 1000 words...

to dough development, the process of developing the gluten network in the dough. Mixing, kneading and fermenting all develop gluten--just at different rates with different degrees of concurrent effects, like oxidation (which also accelerates gluten development, but at the expense of flavor). When Calvel says underdeveloped, think of a crumb more like a cake than a bread.

You need to temper your conclusions somewhat though as Calvel is mostly writing about 63-68% standard baguette like formulations. Your higher hydration doughs will always be slack. By the way, it is a fantastic book, an industry standard; The Taste of Bread; Raymond Calvel; 1999.

Through the power of the "internets" I can shop for UK flours from the middle of the US of A. :) Asda Strong White Bread Flour indeed has added ascorbic acid. Kilo for kilo, all other things the same, it will mix differently from a flour that does not have added ascorbic acid. I'll always be amazed how little of an additive can affect things. So, in my semi-pro, semi-amateur opinion, you were not comparing apples to apples. Flour manufacturers are pretty good at what they do, their products are consistent, even the "value" products. Occam's razor says look to the obvious: user error.  

Your loaf looks good, the large holes look like those in a rustic dough that has not be overhandled. More stretching and folding will degas the dough and distribute the gas cells more evenly throughout the dough giving a more even crumb. The resultant dough will also behave differently than a more airy dough: think about it, the viscosity, thickness, if you will, of air is much less than dough.

I started off making a lot of long fermented minimally kneaded country style sourdoughs with hydrations on the order of 75%-100%. Essentially, no knead formulations. I tend to be biased in that direction as you might have noticed from my comments. Recently, taking a class, baking under the auspices of a CMB (certified master baker), and using a bigger mixer (and a deck oven--ooh la la!) I have developed a better appreciation of what dough development is all about. There is a lot of latitude with a high hydration slack dough; I have made many that were likely underdeveloped but since I was looking for a highly irregular crumb and to minimize oxidation, I didn't notice. Flavor, of course, was and is paramount. They were developed enough that the crumb was not gummy, but in retrospect, I think would have benefited from a little more kneading or folding, i.e. yielding a lighter crumb.

I buy unbromated/unbleached flours, sometimes enriched or with added diastatic malt, but usually without any dough modifiers, like ascorbic acid. The acid is not a big deal, but I don't need it. If I understand correctly, it found its home in the baking business with those that want good volume and to minimize processing time. Calvel doesn't seem to have a problem with it as it is a way to minimize mixing time with its accompanying oxidation. Those of us fermenting overnight shouldn't need it. You seem like a serious home baker, time to start reading labels. lol.

and, as usual, I reserve the right to retract anything I write without consequence. lol. It is tough to troubleshoot without actually being there. Everyone here will tell you, bread baking is all about touch. Sure, there is chemistry & biology, but it comes down to "what does the dough feel like." Do two doughs; both the same except for the kneading/mixing. A control is always nice and eventually through experience you are going to have this formula nailed; then, no matter what you change, you will be able to predict your result. Read TXfarmers baguettes posts, that will give you a good idea of what it is like to develop a bread. She is absolutely amazing; her breads & pastries are truly awesome. 

and they all affect each other! I made the same loaf 2-3x  a week for over a year; I didn't set out to do that, but in hindsight it was a good move and taught me a lot about bread and, obviously, that one loaf. lol. Shaping and dough handling can be learned from a book, but can only be perfected on the bench. There is a reason why professional bakers make it look so easy and often deceptively simple: try making hundreds or thousands of something--every week or day! You are building a good base, keep it up and you will become a master of your formula.

Good bakers introduced me to the old adage: it is hard to overknead a bread: you'll give out before your bread does! I don't think getting good dough development with higher hydration breads and long ferments is much of a problem, especially if it is done at room temperature. Gluten development continues in the resting dough all by itself (as does protease catalyzed breakdown, but, IIRC, that doesn't seem to be a factor until much longer times.). Try making a liquid starter and notice how its strength changes over time. Fermenting for 10+ hours is a lot of time for the yeast and bacteria to multiply; it doesn't take much. A 1/4tsp of dry yeast will leaven 350-450g of flour over 12-18 hours with good flavor at room temp (23-24C). Off the top of my head, I use about 15-20% baker's % of a 75% hydration starter to leaven a sourdough; 0-2 hrs room temp w/8-12 hours in the fridge . If I did it at all at room temp, I would cut the starter down substantially. I don't like to go much higher than that as the dough gets too strong.

Try making baguettes with your dough. Do it a few different ways: degas thoroughly & tightly shape some, minimally handle some others. It's a good way to see the difference.