I've been baking whole-grain sourdough bread for years, but due to
requests by friends I have recently been playing with 100% white flour
sourdough. I started by converting my whole-wheat starter to white
flour, using bread flour to feed it because I intended to use bread
flour (KA brand) to make the actual dough, and I figure I ought to
feed the starter with the same stuff I intend it to feed on in the
dough. Plus, I figured the diastatic barley flour would help the
critters break down the starches.

Well, the starter was pretty limp for a few days, but after several
refreshments it seemed to adapt to the new environment and became
quite active. Now, after a couple of weeks of regular feeding it is
very, very active: When I refresh the starter, I quintuple it (by
weight: 10g starter + 20g water + 20g flour), and within 3 hours at
room temperature (about 75F/24C) it has more than doubled, assuming
the inoculum was reasonably fresh and active already at the time of
feeding (I've been feeding every 12 hours). Bread made with this
starter has great volume but the dough rises so quickly that there's
hardly any time for acid formation and the bread has only the
slightest hint of sourness. I suppose that might be the holy grail
for some sourdough bakers, but when I want that kind of bread (and I
often do!) I just use commercial yeast.

I'm wondering if it might make sense to maintain the starter with
all-purpose flour instead of bread flour, so that the starter doesn't
have the assistance of the barley malt and is therefore perhaps a bit
less active.

On the other hand, perhaps the starter is so active because I feed it
so often, and quintuple at each feeding. Perhaps just letting the
starter go for 24 hours between feedings would calm the critters down.
This might matter more than the type of flour.

Any opinions? What kind of flour do you feed your white starter?

--
Randall