Very Yeasty Starter
I have been propagating a 100% white flour 60% hydration starter for a few weeks for use in SF sourdough recipes. I've become tired of that tack, so I let the starter sit in my drinks fridge at 10 C for about 4 days, unfed.
[Edit: It also had 1% salt]
Today I took it out, baked it up, and ate it. Big oven spring. No sour taste. Massive taste of too much yeast. This is the first time I've tasted that classic yeast taste in ages, the taste like you dumped in a commercial pack of yeast.
I'm wondering why that environment was so favourable to yeast.
Hydration: I've heard mixed opposite opinions on this, but never spent much time with stiff starters to see for myself. I now think that low hydration lowers the LAB:yeast ratio (flavors yeast), but slows everything down. Is that correct?
Over fermentation: I've heard once the pH gets too low, the LAB stop but the yeast keep on reproducing. This could explain the dominance of yeast flavor. The dough didn't taste sour, but there might have been a low pH nonetheless but also a low TTA and so not noticeably sour... getting a really sour bread is notoriously hard, so it shouldn't be too surprising that this wasn't.
Temperature: I've heard that middle temperatures like 23C or so minimize the LAB:yeast ratio, but that LAB outgrows yeast at every temperature. If that's true, the other factors must have been more significant.
Is this in line with your expectations? Do you have better explanations or theories?
I forgot earlier, but this starter had 1% salt. I'm pretty sure salt inhibits LAB more than it affects yeast.
That's not really a huge news - yes, dead yeast will ferment sugars when the cell walls are broken, because their enzymatic machinery will still be there. Eduard Buchner was awarded a Nobel Prize in 1907 for discovering this. So even if osmotic shock really destroys the yeast, with sufficient loading you can still get rise.
"Big oven spring. No sour taste."
I've had that happen. It's why I've given up on starters.