This starter was made about 24 hours ago. Lot’s of little bubbles still rising, but as you can see in the images the mini-krausen has fallen and there is a bit of yeast on the bottom. Should I keep it out until all bubbles stopped?
I’m planning on popping this into the refrigerator for a few days for what it’s worth.
Video link here https://vid.me/f0Iu
Pictures…
As I have mentioned before, making a starter is not the same thing as making a batch of beer. The goal of making a starter is increase yeast cell biomass, not produce alcohol. There is nothing to be gained by letting the starter ferment beyond the point where maximum cell density is reached, which usually occurs around or before 12 to 18 hours.
Yup, fridge time
S. Cerv.
In your opinion, is the fridge step harmful or helpful? I get the argument that the starter (at least the stirplate ones) may have oxidation off-flavors or DMS, but if those are not present - is it better to pitch the whole active starter? Or crash, decant and pitch the ‘sleepy’ yeast?
Note - I usually decant, but today, following your advice of the 12-18 hour growth line, and confirming with a yeast count I just chucked in the whole thing into a dubbel. No off flavors detectable in the starter so I figured what the heck.
Definitely looks like you could cold crash it. I prefer to let the starter fermentation fully finish as well before putting it in the fridge.
Cold crashing the culture is not a problem. It’s up to you to make the decision to cold crash or not. I usually cold crash for at least a few hours at 4C, but that’s only because it makes starter timing easier.
Quick update and question…the starter has been in the refrigerator for about 24 hours (~40 degrees F). The odd thing is that there is still a (small) amount of active CO2 rising from the yeast cake. The yeast cake looks about the same as it did before the crash and there is still a fair amount of foam on top of the liquid.
Thats possible and just fine. Probably your fridge is warm enough and tge yeast healthy enough that its still working. No worries. You’ll be good to go on brew day
As Jim mentioned, a small amount of CO2 production is okay. Lowering the temperature to 4C (39F) does not completely arrest cellular activity (yeast cells need to be cooled to -196C in order to arrest cellular activity). It merely slows metabolism to the point where the cells should sediment. Some yeast strains may need to be cooled to 3C in order to force sedimentation.