After another day, the mixture is less brown and more bubbly. Both of these traits are satisfying, since the brownness really did not look appetizing. The bubbliness assured me that things were working as they should be.
This picture was taken after I stirred up the goop. It felt satisfyingly thick and full of activity.
This is the part that bothers my thrifty (sometimes) soul. You have to dump out almost all of the active goop, and add more flour and water. By the time I'm ready to make bread, I figure I'll have thrown away about 10 pounds of flour.
Since there's very little actual bread-making activity going on around here, perhaps you'd like some random information about sourdough. (Robertson doesn't like to call it sourdough because he doesn't like sour bread, and bread made with "sourdough starter" doesn't have to taste sour. He just calls it a starter, or a "leaven.") If you want to Frenchify it, you could call it "levain."
It's not really yeastless. The starter works because it captures wild yeast that's floating around in the air. Everywhere. Yes, in your house too.
Rumor has it that you can speed up the sourdough process by spitting into the mixture. I swear that I didn't do that.