Why discard starter?
I am fairly new to bread making and have been working with both the Ken Forkish FLOUR WATER SALT YEAST book and Tartine's Book 3 on using ancient grains.
One thing that mystifies me is the vast quantity of flour that must be thrown out in the course of both their processes for creating levain. I can't imagine that people in former times who invented these processes could be so cavalier with their flour as to thrown away hundreds of grams of it daily. Forkish says to think of it as "spent fuel," but since the part you're throwing out is exactly the same as the part you keep and keep working with, it is apparently not completey "spent."
I would appreciate an explanation. Thanks!