Just wondering what type of flour is better for feeding sourdough starter. Regular or bread? Thanks for any input. Jim
It really doesn't care. Yeast consume sugars broken out from the starches in the flour... the gluten levels will have little effect on them. I feed mine AP and it's quite happy.
Shorter answer: it really doesn't matter. Bread flour or AP will make the beasties your starter just as happy.
Longer answer: The short answer is valid if you are simply talking about feeding a starter before putting it into storage, or putting it back into storage, or between bakes. If you are talking about the first build for a dough, then you should check the recommendation in the recipe you are following. Bread flour, because of its higher gluten content, will be able to stand up to a longer ferment than AP flour before the dough "goes all to rags". In other words, acids produced by the bacteria in the starter dissolve the protein strands that make up the gluten. AP flour has less gluten to begin with, therefore it is more susceptible to dissolution in a shorter time than bread flour, which typically has a higher gluten content at the outset.
I think it is up to you. I use bread flour, otherwise my starter seems to be watery. Which is not necessarily a bad thing but I prefer it to be a little more batter like.