I am making a fairly wild guess here, but maybe you should cut back in the starter. You are making your sponge with 1 cup starter, and 4 cups flour, and letting it work overnight, so you are ending up with 5 cups sourdough the next day. If you were to cut back the SD by half a cup, and add another half cup flour, you would still have 5 cups, but not such a concentration of *sour*. I think. But I could so easily be wrong. Also, my "Alaska Sourdough" book says that adding baking soda helps to neutralize some of the sourness, but I don't know that I would want to do that with bread; works with pancakes and English muffins though.
I must admit that I haven't made much *totally SD* bread; I usually make a SD and yeast hybrid.
I must admit that I haven't made much *totally SD* bread; I usually make a SD and yeast hybrid.
- BB, the flour doesn't need beasties of its own; the starter supplies them, and the flour supplies the food for them.So it's not possible that the white flour is lacking beasties and microorganisms and because the SD is being fed the same thing that it has 'grown' or evolved to the point that it is at right now, and needs to get back on a different track?