Crabapple Sourdough Sponge: first try

This blog is a record of my ongoing experiments with sourdough bread. I'm getting tips from a few sources, including my own experience, my mother, and Sandor Ellix Katz's book Wild Fermentation. What I'm going for is a good-tasting, whole-wheat bread made without any commercial yeast, and with all local ingredients (I live in Montpelier, Vermont). It's mostly just for my own entertainment, but also because I'm doing the "localvore challenge" in a couple of weeks and would like to have bread to eat.

Six days ago I mixed one cup of local whole-wheat bread flour from Gleason's Grains with one cup of warm water and two crabapples' skins, unwashed, picked from the tree in our front yard. I used a wide-mouth quart mason jar, to be able to see what was going on in there, and screwed the top down just enough for the threads to catch, but not enough to make an airtight seal. I also mixed a jar of just flour and water, leaving out the crabapple skins, to see if there would be a difference.

The jars stood on the counter away from drafts and direct sunlight for three days. They were both bubbly and fragrant when I lifted the tops. The one with the crabapple skins smelled like apples, and a little like alcohol; the other one smelled a little like cheese. I strained the crabapple batch through a wire sieve to remove the skins, which went into the compost, and then poured the starter back in its jar. That afternoon, and for the next three mornings, I stirred two tablespoons of bread flour into each. I used the same fork to stir the flour into both jars, but always started with the no-crabapple batch.

After being stirred, the starters slowly separated into two layers visible through the jar: the solids sank to the bottom, and a brown liquid sat on top of them. Over the day, bubbles formed and the solids were carried up to the surface. After a while, almost all the solids formed a bubbly mass above the layer of liquid, except for a thin, light-colored dusting at the bottom of the jar. The bubbling-up took about eight to ten hours in the crabapple batch, and more like fourteen to sixteen hours in the no-crabapple batch. The smells of both batches got stronger: the crabapple batch, when it's ripe, now smells almost like acetone.

Today at six in the evening, once the crabapple batch had bubbled up (I fed it this morning around seven), I poured off a cup of it into a mixing bowl and set it aside while I poured the rest (about a third of a cup) into a fresh jar and mixed it with a half-cup of water and two more tablespoons of the bread flour. The cup of starter in the mixing bowl was mixed into my "crabapple sponge:"

---Sponge---
1 cup starter
2 cups warm water
1 Tablespoon maple syrup (local)
3 cups whole-wheat bread flour

I stirred them thoroughly with a dough hook (beautiful thing), covered the bowl loosely with a cotton cloth, and set it aside.