hello

i've created a healthy starter following Susan's instructions over at Wildyeast blog

I would like to know, why must we throw out part of the starter when growing it?

Is it for biological reasons? Does it strengthen it somehow?

Or is it only because you'd otherwise end up with a room full of the stuff?

For example, after day 2, I had 300 grams of starter. I then kept 75 grams of it to which I added 75 grams of flour and 75 grams of water, as instructed. What would happen if I kept all 300 grams, and added 300 grams of water and 300 grams of flour?

-Pietro