Wondering specifically about yeast cakes and starters?
-Sometimes I rack and just leave the cake…with a thin cover of beer…in the carboy for a few days before I harvest it and transfer to mason jar for the fridge.
-A few weeks ago I made a starter, got busy, and forgot about it in the back room where it still sits in the flask with “beer” on top.
I imagine that temperature is key…that room stays about 60-65 this time of year.
What do you folks think? Am I OK with this rather laggard treatment of my yeast or am I actually harming the yeast and risking something foul?
Is actual refrigeration critical in the above cases?
I used to think that some beer left on yeast would protect it some. I wouldn’t rinse yeast real well and would refrigerate yeast with a layer of beer in mason jars. I had one grow mold on top of the thin layer of beer even though I was extremely careful with sanitation and boiled all rinsing water. Yeast I’ve left with no beer on top has never become infected.
I would think that as long as there’s nothing wrong with the appearance of your starter you should be fine. I would cold crash it and decant though. Anymore I never leave yeast in a carboy for more than a day if I plan to reuse it.
I have stored yeast in the fridge with beer on top hundreds of times and never seen mold or an infection. I have to believe it was due to something other than leaving yeast under beer.
I really need to check my notes from that beer and see what it was. I may have been experimenting with spices and it may have inflected the batch. I just drank it too fast to notice. The yeast was in the refrigerator longer than it should have been, I’m sure.
sure it’s detrimental. but will it make everything go pear shaped? no. your viability will be very negatively affected though. any contamination that is in there that likes temps ~65 but hates them lower than 40 will grow much faster. The Yeast themselves are more active and there for will starve faster when they don’t have any food left.
But that doesn’t mean you can’t use the yeast. On the couple weeks old starter at room temp I would remake the starter before using it though.
I’m assuming autolysis occurs at warmer temps without a foodsource. To me this includes room temp. At this point it’s better to make a starter out of it (the cake) rather than a repitch. Less chance of off-flavors developing.
Time shouldn’t matter. I’ve stored yeast slurries for 6 months or more with no issues. I have to burp my containers every so often as the yeast seems to continue producing CO2, which probably helps create an unfriendly environment for other things to grow.