Layer of yeast on top of sourdough discard?
Most of the time when I feed my sourdough starter I find uses for the discard, but on occasion I don't have time or good ideas, so I put it in a separate jar and store it, with a tight lid, in the fridge.
Yesterday I took the discard jar out and found something I've never seen before: a layer of dry, off-white, stringy material (see photo), with the distinct smell of baker's yeast: 
Hooch often appears in the discard jar after a few days, but this is definitely not that. It also doesn't look like any type of mold I've ever seen - and definitely doesn't smell like it either.
Luckily this is just the discard jar and not my active starter, but I'm really curious. Could this be yeast? If so - where could they have come from? And how have they grown on top of a lively sourdough culture?
N.B.: I had made this starter from scratch (i.e. flours and water) without using yeast or any other additives, and have never seen this in the 6 months I've been using this culture
Best Answer
Sourdough culture is partly yeast. Since this container was made up of sourdough taken out of your primary culturing vessel, and not fed, that is probably dead yeast that floated to the top. After all, it hasn't had any source of sugar since you put it in the fridge.
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Quick Answer about "Layer of yeast on top of sourdough discard?"
Sourdough culture is partly yeast. Since this container was made up of sourdough taken out of your primary culturing vessel, and not fed, that is probably dead yeast that floated to the top. After all, it hasn't had any source of sugar since you put it in the fridge.How do I get rid of KAHM yeast sourdough?
Kahm yeast is a harmless yeast which can develop on the surface of your sourdough starter. It's not ideal but can be scraped off the top.What is the layer on top of sourdough starter?
Bakers refer to the liquid that accumulates on the top of sourdough starter as \u201chooch\u201d. That's because it is an alcoholic byproduct produced by yeast during its fermentation process. Hooch is perfectly safe and simply means a starter hasn't been refreshed recently. In other words, it's hungry.What is the black stuff on top of my sourdough starter?
The dark liquid is a form of naturally occurring alcohol known as hooch, which indicates that your sourdough starter is hungry. Hooch is harmless but should be poured off and discarded prior to stirring and feeding your starter.Can I drink sourdough hooch?
In sourdough, hooch is a light liquid that is thrown off by a sourdough starter. Since sourdough starters have yeast in them, and since yeast produces alcohol, there is some alcohol in hooch, but you have to be pretty hard up for a drink to even consider drinking hooch.What's that liquid in my starter?
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