I am having a terrible problem, I think. My sourdough has turned into a gel like substance and I don't know why. It's possible I might have gotten a peppering of whole wheat flour in it as I used the same measuring cup that had whole wheat in it prior to using it to dump white flour in my starter. Aside from that I had used 3/4 of it and filled it back up with flour about 3 cups worth all at once. That shouldn't have been a problem though. It's 120 year old sourdough and I am desperate to save it. It's never been gel like before - always just frothy and smooth before. Can anyone help me?