"Roy" wrote in message =
oups.com...

... I have seen natural sourdoughs leavened with the
final dough flour to starter ratio of 55/45 and it really ferments
and proof really fast as if yeast was added; when the fact is ii was
just 100% naturally leavened! ...

Aha!

Could that be taken to mean that the "sponge" method can be applied
to sourdough baking?