Many of you might remember the question I asked last week about a struggling starter. I baked with it on Saturday and it yielded an very much *unrisen* loaf.

I switched from the unbleached white flour to the Tartine method-- 50/50 whole wheat and unbleached white. Immediately the starter showed lots of activity, rising and falling beautifully and always full of bubbles.

I baked with it this morning-- here was my schedule:

Tuesday Morning (6:30amish) : mix levain, mix dough for extended autolyse. Both at room temperature.

Tuesday Evening (5:30pmish): mix levain into dough (levain was young and bubbly and smelled awesome at this point), add salt, set for bulk rise. The bulk took place in my oven. Periodically I would turn it on and immediately turn it off, so it sat somewhere in the 80 degrees (f) range. Every half hour for the first two hours I did stretch and folds, and after I did it once. The entire bulk rise was approximately 3 hours.

By that time I had to get it moved to the final rise because it was time to go to bed. I could tell through the shaping that it was underproofed. Nonetheless after the bench rest I put each boule into baskets, covered them, and set them in the fridge. This was at 10pm.

Wednesday morning (5:30am): I took the loaves out of the fridge and turned on the oven with my cast iron in it. By 6am it was ready and I baked the first loaf.
It rose only in the very middle, and not very much at all. The loaf was dense and had large holes sporadically throughout, and it was *really* sour.

The other loaf-- the one that sat out at room temperature while the first was baking-- didn't rise at all. It's a brick.

I've attached a picture of the crumb of the first loaf so you can see what I'm talking about.

My question is two-fold:

1. How can you tell *during the bulk rise* that your bread is adequately proofed? I can find loads of info on the internet about signs of under-proofing and over-proofing, but never what it looks like when it's perfect.

2. Why did my bread taste so sour? I was told that the longer, cold final fermentation would help develop a more mild, tangy flavor, but I got the opposite.

Thanks, bread experts!