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Weird mold or yeast? on starter

clober's picture

Weird mold or yeast? on starter

Hi all,

My sourdough starter grew this weird stuff on top after about two weeks of idleness (I fed it, then left it for two weeks) at room temperature. Does anyone know what it is? 

Thanks in advance!


Abe's picture
Abe (not verified)

Seem to remember an older post from a few years ago talking about this. I'll have to find the specific one but from what I remember it's yeasts morphed (for want of a better word) into some kind of spore due to certain conditions. 

Is there a healthy looking part of the starter beneath the weird looking stuff? If there is try carefully getting rid of the top. Get some healthy looking starter below and feed it back to health transferring into a new jar or thoroughly clean and sterilise this jar before transferring it back in.

Why did you leave it at room temperature for two weeks? Always store in the fridge. Hopefully you might be able to bring it back to life. It might take a few days in which case you'd be just as better off starting a new one or you could try both and see which is successful the quickest. 

PrayaDubia's picture

I saw pictures of this on the Facebook group, Perfect Sourdough. Per the posts I saw, kahm yeast forms on neglected starter. It is non-toxic but unpleasant tasting. You can still revive your starter by using a small amount of the starter underneath the surface. Hope that helps!

Southbay's picture

Two weeks without a feeding at room temperature is waaayyy too long. If I skip two days, I consider my starters to have been neglected in Dickensian squalor.  Two weeks is like your starter is a small business here in Cali that’s been starved out of existing by lockdowns. Feed it every day or fridge it. 

Debra Wink's picture
Debra Wink

Hi Carolyn,

When I zoom your photo to get a closer look at the texture, it loses too much resolution to say for sure, but my presumptive diagnosis would be mold. Does it look more like silk fabric (mold) or soft cheese (yeast)?   Also, did you see any conidiophores (mold)?

mold on raisin water