This Bread Came About as the result of some interesting experimentation I did some years ago at the King Arthur Flour Bakery. It’s a good example of how the baker can make a small change in process and significantly alter the final flavor. Normally, as we know, ciabatta is leavened using commercial yeast, yielding gentle aromatic overtones in the finished bread. The present formula uses liquid levain along with some commercial yeast, resulting in a subtle yet distinct tang. That mild tang, combined with three other elements—toasted wheat germ, raisins, and toasted walnuts, fills the mouth with abundant sensations. Omitting the bakers’ yeast and increasing bulk fermentation to 2½ hours alters the final flavor of the dough even more perceptibly, resulting in bread with a more forward acidity and slightly reduced volume.