I'm trying to capture the flavor of the really sour San Francisco sourdoughs of years gone by, such as Larraburu. In a recent effort I was so close but so far away. The good news is that I had the flavor pretty much nailed. The bad news is that the bread didn't rise. Now we must ask why.
In my pursuit of a really sour flavor, I'm afraid I let the dough proof way too long (actually I fell asleep and by the time I got up it was too late.) The dough had proofed for about 12 hours at around 86 degrees F and had turned to mush. It went in as dough and came out as batter. No amount of added flour or kneading could save it; it was gone. I'm thinking the 12-hour proof is the reason why. Is this a telltale symptom of overproofing? I baked the loaf and the lesson learned is that the long proofing time was likely responsible for the flavor being just right. I'm thinking a lot of yeast spores died in those 12 hours.
The next day I made another loaf but proofed for just 8 hours (an alarm clock is your friend). This loaf had somewhat lower hydration. This time it went in as dough and came out as dough and had a pretty good rise and texture. The flavor was good but definitely milder than the previous loaf.
So my dilemma is this: how to maximize sourness by using a longer proof time without the dough turning to batter and failing to rise? First I must answer the question of whether overproofing was the reason my dough went mushy (I suspect it is).
The Larraburu bakery proofed for 4 hours at 105 degrees F, but the question has been raised whether such a high temperature would kill some of the microbes (including L. SanFran which gives it the sour flavor). A competing S.F. bakery proofed for 8 hours at 86 degrees F.
I am thinking about arriving at a good proof time experimentally, increasing it by one hour each time until I find the proof time at which the dough turns to batter. For my next loaf I was going to try a 9- or 10-hour proof.
Another way to increase the sourness which I haven't tried would be to add diastatic malt which is already in the flour I'm using (KA unbleached all-purpose).