I received the starter in early June this year. I feed 2 parts flour to 1 part well water. The flour is sometimes organic whole wheat, sometimes white flour. I keep it in the refrigerator. I feed once a week, but sometimes longer. It had been about two weeks when I opened it and saw stuff that looked like yeast granules. They are tan in color. I fed it and let it sit out for a few hours, then back in frig. I just took a look at the starter and it looks filmy, like the same thing is developing. It has a strong yeasty smell. Is this mold? Is it still usable?