Starter has developed cheese smell
I've been baking with my starter for the last three years. I do the same thing every time I feed it and either store it in the fridge or on my worktop with a lid on. About 4 weeks ago I decided to start making kombucha and whilst it takes great, I've decided not to continue with it. I stored the kombucha scoby in the fermenting jar on the same work surface, about 5 feet away from my sourdough starter.
On Thursday night I opened my starter to find it smelled of sweet cheese and the starter all around the edge had taken on a grey tinge, and the top had developed a skin. No mold. None of the lovely acidic smell I'm used to. I removed the skin and scraped the grey starter off. Took a spoon of the 'ok' starter from the middle and put it in a new jar. I've been feeding it my usual organic dark rye since then but it's still smelling cheesy. It's producing bubbles as usual.
Could I have some sort of cross contamination from the kombucha going on? Because my initial thought was it smelled unusually sweet (not the sweet smell of starter but more like sugar). I have moved the kombucha scoby out of the kitchen now. I also thought that I might have fed my sourdough starter buckwheat by accident as the flour bags are almost identical as they come from a local mill. Could feeding something like buckwheat only once cause this?
I've read a few other posts, mainly from people just making their first starter who have this cheese smell. I really don't want to get rid of this starter. Should I add an acid like lemon juice, or just persevere with reducing down to minimum amount and feeding every day?