This morning I proofed and baked  Jeffery Hamelman's "Sourdough Seed Bread" from his book, "Bread." This is basically a pain au levain with toasted seseme and sunflower seeds and a soaker of flax seeds. Hamelman is clear that this bread's flavor benefits from slow fermentation. You can spike the dough with commercial yeast, but it's better not to. You can bake it the day it's mixed, but it's better to let it cold-retard. I went for all the flavor I could get, and I got it in abundance!