Working with yeast to make bread has often been an intimidating endeavor for people. Unlike baking powder, baking soda and other chemical leavening agents, yeast is living and more difficult to control. Before the advent of commercial yeast in the 19th century, people used naturally occurring yeast to make bread. A medium of flour and water was used to culture the yeast and the symbiotic bacteria, this was called a sourdough starter or levain. The acidity of the sourdough starter kept harmful bacteria from growing it and enabled the yeast and bacteria to live without much competition. Bread made with levain is more flavorful than bread made with commercial yeast, however it takes more time and is more challenging. You need to allow the dough to ferment sufficiently in order to have enough flavor, but you can easily end up fermenting too long and end up with bread that's as sour as vinegar.
I was inspired by the beautiful blog Tartine Bread Experiment to try and make my own sourdough bread this summer. One summer of experimentation has convinced me that we are constantly learning new things in life. When you think you finally think you've got the handle on something, you fail or the results come out differently than what you thought they would be.
