Starter contaminated?
I keep my sourdough starter in fridge - and even if it's not fed for a few months it always comes back quickly when I start feeding it again. However this time after not baking for a while I noticed that I hadn't shut the lid off in the jar properly and when I looked at the starter the top layer was completely covered in what looked like mold (blue/grayish) and smelled very strongly like yeast instead of the typical very acidic/acetone smell I was expecting. I tried feeding it (1tsp starter/40g (50-50 whole-grain/plain) flour/50g water) and noticed that it rose very quickly, almost tripled size in 3hr and again strongly smelling like yeast. I wonder if it got contamined by baker's yeast somehow? I had a pack of fresh yeast open in the fridge a few weeks ago. Is there any way to rescue it or should I start from scratch?
If you leave it on the counter for a while (like a couple days) does it go sour again? (This will bring up the lactobacillus population.)
If not, start over.
Thanks! will give that a try. Left it overnight still smelling quite yeasty in the morning but bit more sour maybe. Usually when I remove it from the fridge it would take 8-12hr to double after refresh and then I would use that for baking. This time it just tripled and almost overflowed in 3hr even with a such a little starter amount, I stirred it to knock the air out and then it doubled again in 2-3h. I'll probably just start another starter on the side, just in case..
Just to give an update on this I ended up creating a new starter from scratch as the other just didn't smell right. Got to bake with it first time today making some buns and it performed great, seems more active than my old starter for sure. Didn't really use a set recipe for creating the starter, started with 40g whole wheat/50g water, let it sit around 3 days and then feed it at 1:1:1 with white flour around every 24h and then eventually 1:2:2. Took about 1 week to get it rise predictably.