I made ciabatta today, sourdough. And it came out a bit sour, for the first time with the starter I developed about 4 weeks ago.
Here's what I did.
I made a lot of very liquidy sponge, I guess you could call it a poolish, and left it out for the day, then refrigerated overnight.
This morning the poolish had some thin "hooch" type stuff in the bottom and I mixed it all in and used it all in the bread. I could tell it would be sour when I saw that.
I then made the dough quite liquidy. I used 1 cup of this very liquidy poolish to 3 cups flour. I use the food processor and I used enough added water to make sure it just barely formed a ball with a lot of dough trailing the ball.
The dough was almost a batter.
During the primary ferment (about 8 hours in the basement at about 70F.) I folded a
few times -- put on a floured board, stretched and folded. I continually wet my hands so they wouldn't stick and I floured the countertop also. This was the only way to manage such wet sticky dough.
I proofed about an hour on cookie sheets lined with parchment. When I baked, I did so first at 550F. on the stone but I just stuck the cookie sheet on the stone.
I steamed in a pan at the bottom of the oven.
They puffed up very well, great oven spring. They were very light with lots of big and small holes. I was surprised how tender they are. And they tasted a bit sour, for the first time since I've been trying this. (The last ciabatta I made using a mixed starter/yeast formula but I wanted to be a purist on this and only use my starter this time.)
So, lessons learned:
1. high sponge to flour ratio
2. develop your sponge and then refrigerate overnight
3. work with very hydrated dough
4. fold dough during bulk fermentation
Next time I will work more carefully in folding when I proof, so there is at least some surface tension in the dough. I don't think I had enough surface tension. Next time, I will fold the dough during proofing, to create as tight a seam as possible with the wet dough, and then turn over so the seam is at the bottom.