Cra-zee oven spring
Most of the bread I bake is either the Whole Wheat Levain recipe from Hamelman's Bread or the Basic Sourdough recipe from BBA.
Generally I like the whole wheat bread better, particularly since I switched to a mix of mostly white whole wheat with just a little red coming from the starter (I feed it with cheap, but fresh, red whole wheat flour I get at my grocery store). But I've been playing with some tweaks to the white-flour sourdough, particularly since I bought a bunch of moderately-priced organic bread flour (the Sperry product) from NY Bakers.
The organic bread flour is really more of an AP flour at 12% (nominal) protein. It's just wheat, no malted barley flour to correct the falling number. I've had slightly denser loaves than I was used to from conventional flour and a bit of a problem with the crust not browning as much as I'd like.
I made two slight tweaks to the recipe today:
1) Rather than making a stiff levain and retarding that overnight, I simply mixed the full recipe except the salt using my 100% hydration culture and retarded that. In the morning, I let it come up to room temp, added the salt, kneaded, and let it rise. I have been using a pretty long bulk fermentation time -- 5 hours at 80F in my bread machine -- since switching to the organic flour, and that's what I gave this loaf.
2) I used about 1/4 All Trumps and 3/4 organic flour. This should have bumped up the protein level to about 12.5% -- about like KA Bread flour -- though what I was really looking for was slightly better browning from the malt used to bring the All Trumps within spec.
I did get somewhat better browning, and there was a change in the texture of the bread -- less chewy and slightly softer. The other thing I got was completely insane oven spring even though I slightly overproofed the loaf -- the boule popped up until it almost hit the next rack in the oven!
Since the net protein content wasn't that high I'm not sure which change was responsible for the wild oven spring. I guess I'll redo the experiment twice and see which change it was, or whether it was both in combination.