Calling sourdough starter experts!

[stclair]

As I can’t find yeast for love nor money, I’m on day 3 of a sourdough starter (from bbcgoodfood recipe). What I am confused about is the pouring off of half the starter when ready to bake. Is this to be used to add more flour and water to keep the starter going? Otherwise It seems wasteful! If it isn’t, why pour it away?

My most recent effort. One is 100% high grade white, the other 100% wholemeal. My recipe uses 84% hydration.

The result, especially with the white loaf, is quite chewy. Another interesting thing: the sourness almost vanished from my starter over summer, but it's now returning as the weather cools off.

That looks really good @TomPinch. Great rise
I’m still doing sourdough, and after a few experiments with other recipes ( usually ending in disaster) still doing the river cottage method. My main area of improvement has been working on my starter, doing daily feeds and getting it nice and active. I usually go for a 65% hydration.
My biggest disasters have been when following recipes from US based writers. Anyone else found that? I’m wondering if it’s a flour thing, or maybe the fact that the recipes are often written with electronic dough mixers in mind.

Marking place!