Has my sourdough gone moldy? Today as I checked on my sourdough starter, I noticed some dry white patches on its surface. Has it gone moldy? If so, is it safe to just scrape off the mold and use the remainder as usual?

The sourdough smells cheesy / yeasty, nothing that yells "I've gone bad!" at me. There is no liquid on top. I've left the jar open for the last two days covered with a cloth, can it have anything to do with it?


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Scouring the internet a bit more, apparently the crust was some nitrogen-hungry form of yeast.

However, I did as suggested in this similar question, discarded most of the sourdough and used a bit of it to start a new one. Wish me luck for it!