Sourdough starter can be fairly forgiving. If you’ve placed it in the refrigerator to take a break from bread baking, you may find yourself wondering just how long it’s been lurking in there when you’re ready to start baking again. First thing to do is pull it out and take a look at it. If it’s been in there for a long while without feeding, it will likely have an almost greyish-looking liquid called “hooch” sitting on the top. This is totally normal and doesn’t mean that the starter has gone bad. It will smell yeasty, reminiscent of beer.
If you see white or pink splotches over the surface of your starter or around the rim and edges of your jar/container, that is likely mold and it will smell off. At that point, it should be thrown out and you should start from the beginning. (See our post about easily starting sourdough from a packet.)