It's amazing how little changes can have such huge impacts on bread making (I shouldn't be surprised though as I've all too often made tiny changes and seen my share of drastic results.) Still though, just when you think you've got it, the "you" being me in this case, you (me) introduce a small change that, you (you) guessed it, impacts the finished product, dramatically. We'll start with "five degrees."
Since the entire production is done out of my home, I have enlisted the help of an extra refrigerator and a large chest freezer for my cold and warm proofing (the cold fermentation being done in the frig and the warm, incidentally, being done in the chest freezer with the help of an appliance light bulb.) I recently purchased a Johnson Controls digital thermostat control unit for the frig and decided to start with a temperature of 45 degrees. I had been proofing my loafs for approximately 20 hours at 40 degrees. Not a big difference, right? Well, yes. Most fermentation activity ceases to continue at or below about 40 degrees. This includes both yeast and bacterial fermentation. However, raising the temperature just five degrees allows a small amount of fermentation to occur (bacterial fermentation increasing more than yeast activity - here's a great article that covers bacterial fermentation .) Over a twenty hour period, that can make a significant difference as I found out. The first few batches were definitely over-proofed. Maybe I shouldn't say definitely, but that's my conclusion so far as I suspect another factor. Thus, the subject of "Round vs. Rectangle."
First, a little bit about gluten strength. Gluten development is a vital necessity when doing long fermentation. During fermentation, the enzyme protease breaks down the gluten network developed during kneading which makes the dough more extensible. If you start with an under developed dough, you're going to end up with an even more under...you get the idea. If your'e fermenting at 40 degrees, protease does not have the chance to attack the gluten structure as actively. What you're really doing with dough at that temperature is suspending it and then reanimating it when it's warmed (or baked directly from the cooler.) However, when you proof at 45 degrees, the bacterial fermentation, including protease activity, increases and the gluten is broken down. It's minute, but over a long period that process can seriously weaken the dough.
Oh yeah, "Round vs. Rectangle." As the amount of dough I knead has increased (this is all done by hand) the container in which I knead the dough is actually hindering development. It's not the shape, but the size. With a 20 QT round container, it's been difficult to get the dough properly developed, even with an extended two hour autolyse. However, moving that process to a rectangular container has made a huge difference. Proper dough development is contributing to better oven spring. The oven spring was missing from what I thought were over proofed loaves.
We'll see how things progress...