One of my chef-instructors told us the story of a famous restaurant that had been around for decades, and was in need of some renovations. During construction, in order to preserve their unique sourdough starter that had been around for as long as the restaurant had, the head chef divided it in half and gave each half to a different sous chef. That way, if one of the sous chefs killed their half (and was subsequently fired, no doubt), the other half would still have a chance at survival.
You see, sourdough starters are serious business.
Let me back up a little. A loaf of sourdough bread has three ingredients: flour, water, and yeast. But so does ciabatta. And a French baguette. So what gives sourdough that distinctive sour tang that hits your tongue when you bite into a nice, hearty piece? That's all thanks to an aged pre-ferment known as a sourdough starter or liquid levain.
Sourdough starters are essentially a forum for wild yeast to gather and grow. In order for them to thrive, they must be fed on a regular basis and with proper care, they can survive for years. Kind of like a dog. Or a child. The longer they survive, the more depth of flavor they will impart to a loaf of bread.
There are two basic ways to make a starter. For either, you combine warm water and flour. Then, you can either add in active dry yeast, or you can simply wait for wild yeast to flock to your creation. Either way, as the starter ages, wild yeast will eventually begin to collect, and different locales will foster different kinds of wild yeast. So, sourdough bread in New York may taste completely different than sourdough bread in Paris, even though the ingredients and method are exactly the same. San Francisco supposedly has some of the best wild yeast in the country.
So why am I telling you all of this? Because I've been feeding one for the past three days. Stay tuned!