I recently started making sour dough in a bread machine acquired from a second-hand shop. Don't scoff at that - I'm a sour dough newbie and so far this bread machine thing has been working out for me! I started a culture using yogurt and flour, so lactobacillus and who-knows-what wild bugs are present. For the first half dozen or so batches, I didn't trust it to rise on its own so I added commercial yeast to the dough (but not to my culture) and the result was OK - nice texture as far as bread machine bread goes, and a bit of sourdough flavor. I even made a batch in which I added about half a pack of Danstar Nottingham left over from a bottling operation. Again, a decent loaf, but nothing special. But last week I tried 2 loaves using only my culture, no added yeast. I had great leavening and the flavor was fantastic. In fact, I'm going to start another loaf right now. What else to do at 3:30 AM when I can't sleep? Grade my students lab reports and papers? Nah. I'm making bread.