Dave Miller on Baking with 100% Whole Wheat
...les can alter the balance between the yeast and bacteria. The longer the starter goes between feedings, for instance, the more the bacteria will dominate. Too much bacteria in the levain and you’ll get a bread that is overly sour and over-fermented (a problem I’ve been having lately). Feed the starter more often or shorten the time between the feeding and using it in a loaf, and you’ll boost the yeast and decrease the bacteria. Some other concepts...