After a 600 mile drive down the east coast, my firm starter gave up on life and got really gooey and sluggish. Poor thing.

I can't afford to wait on its recovery, so I'll forge on without it. I am planning on making a yeasted panettone. I've done this before, and I found that it lacks the depth of flavor that naturally leavened panettone has. I assume (correct me if I'm wrong) that some of this depth comes from lactic acid, which imparts a pleasant tang. I was wondering if any of you have tried substituting buttermilk in place of water to enhance flavor. Also, should buttermilk be scalded beforehand?