Is it the water?
I have had, for several years now, a white flour based starter. Over the last year or so, the sour has dropped to practically nothing. I have recently changed my feedings from 100% white to 20% rye , 80% white. Just to be clear, my percentages are based on weight and the hydration is 100%, thats is equal flour and water by weight. The white flour is a high protein unbleached flour. The rye is an organic rye from a local grocery's bulk foods section.
With the 100% white feedings the starter would double within about 4 hours and my bread rose just beautifully, but they had loss the sour I had. With the change to adding rye flour, my starter rise has slacked a bit to about 8 hours or so and the bread doesn't rise like it used to. I'm less concerned about this for the moment because of what I am about to ask next.
Here's the real question. The starter seems to be coming back on the sour note, but it's not what I would have expected at this point. When I feed my starter I use tap water filtered thru a Brita filter, however my concern is the chlorine level in the tap water. Is it possible that the Brita filter is not removing enough of the chlorine and the remaining chlorine is killing off the bacteria that produces the sour flavor? Should I be letting the water stand a day or so before using it with my feeding flour?
I do have another question and it's not related to water, opaque or transparent? The container I amusing to keep my starter in is a clear glass bowl. Can sunlght be affecting the bacteria? Could it be either stifling their growth or, worse, killing it off?