explosive yeast starter

[SoCal Surfer]

No! It's probably happening just on my starter vessel. The selective pressures are out there and now they want my beer. The hardy-weinberg equation could tell us if the population was evolving on the micro level. But I nerd out on enough crap without starting to see how my gene frequencies are changing in my starter! All I need is a new variable!

[Cliff]

OK! so I stepped up a yeast starter from 500 ml to 1000 ml after finding an old expired vial in my fridge. The 500 ml barely took off. When I stepped it up to 1000 ml, it lagged for a day and then went off. It krausened over the top yet still under the foil. It had dried but I lifted the foil back, wiped up as much as would come off with isopropyl. then I switched the foil with a new foil piece that had soaked in starsan. Am I good or is it toast after coming out the sides? Do bacteria crawl up dried krausen bits, under foil, and into starters?

The bacteria are laying in wait for just that event. They are swinging from the ceiling on little filament strands yodeling all the way to your starter. These bacteria are also unionized so they are the worst of the worst.

No they won't crawel. Bacteria are not autoperambulant like that. They have little flagella that maybe might allow them to move possibly three or four millimeters over the course of a few years - - maybe - if they were going flat out.
So if the outside of the vessel were fairly clean, meaning you had not just handled it after cleaning out your septic system with your hands, you are most likely golden.

[atomicpunk]

They have little flagella

Must be Irish bacteria.