Starter is ailing- what medicine do you recommend?
Recently my firm starter developed a spoiled smell- it has all the smells and appearances of a healthy starter (rises predictably, no visible discoloration, etc.), but added to that is a definite spoiled smell that I would never put in bread. I would describe it as similar to the smell of spoiled milk. The smell is much stronger in the early part of fermentation, after a feed, than it is later in the process.
Luckily, I had a back up in the fridge (I maintain my ongoing culture at room temp) which sprung back to life easily and quickly and is doing well, so I am able to be relaxed about what is going on with that smell.
My first approach was to let the smelly starter sit for two days after a feed, hoping that the desireable microbes would win out over the undesireables. That didn't work. My second approach was to let it go even longer- three days at room temp- after a feed, in hopes that a little alcohol or ketones or something in a underfed, overripe starter might help kill off whatever has taken root in there. That didn't work, either.
So now I'm curious to experiment with it to see if I can find a fix: what sort of medicine would you recommend? I'm thinking of things like salt, freezing, lemon juice, etc. I'll probably divide it up and try a different approach in each jar. Thoughts? Suggestions? Advice?