sourdough starter waste
Hi All, I am making sourdough starter for the first time, using Nancy Silverton's Breads from La Brea Bakery Cookbook recipe. I'm at the end of day 10 (when you really start feeding it) and I am shocked at the upcoming waste. I'm supposed to add about 8 cups of flour in the course of a day, then pour off most of it each morning, keeping only 2 cups, for the next 4 days!?!?!?!
Someone please tell me why I need to do it this way? What's the point of adding so much flour only to throw it out the next day? Is there some chemical reaction that requires volume?