I am an amatuer baker and have been doing so for about a year and a half. My question is, I have a sourdough starter that I have been feeding and the scent has changed considerably recently going from a somewhat sweet to one that is much stronger and not a bad scent but one more on the order of a strong cheese. It has never had a bad yellow liquid or been neglected for a long period of time, but I just wonder how one would know possitively that the starter has gone bad. I am currently feeding it everyday outside and not refrigerating it. I appreciate any feedback in advance.