Starter bubbles, but minimal rise/white patch on top of bread?
I have been baking exclusively with sourdough for about 7 years and had great success. A few times my starter has gone through a slump (usually after some mild neglect) where even if the starter itself is bubbling well after feeding, the dough never seems to reach its full potential, and the finished loaf is more dense with a distinct white patch on top (I use 100% whole wheat flour). The bread tends to have a stronger sour, and tends to dry out faster on the shelf.
In the past this problem has been fleeting, and easily remedied with disciplined feeding and sometimes a reduction followed by an increased food ratio, then normal consistent feedings. This time around I can't shake it. It has been almost 3 months of substandard bread. I haven't started a new starter because I really would like to understand the problem since I know others who have experienced this problem.
My instinct tells me the problem is bacterial, but I wanted to see what you fine folks thought about it. Thoughts?