How to tell if starter is healthy? Liquid Yeast

[saeroner]

I forgot to get the vile shipped with an ice pack (im in Florida). It was warmish when I got the shipment. It's California ale yeast

Made a starter 16 hours ago. Should I turn off the stir plate and see if a yeast cake forms on the bottom?

 

[JonM]

Can you see little bubbles rising to the top?

 

[flars]

Sixteen hours is not an overly long time to have a starter on the stir plate. It might or might not be done. Turn the stir plate off for three hours, then give it a couple of good swirls for aeration. If you get an instant krausen, it is not done. Shaking it will give you some foam, that looks like krausen, but foam will dissipate rapidly.

 

[WoodlandBrew]

A gravity reading with a refractometer would tell you if the yeast fermented the wort. I would let it run for at least 24 hours before crashing. 48 hours would be better to ensure completion. After crashing you can measure the volume of the settled slurry. If you have more than about 30ml (assuming one vial of yeast) then there was growth. You can also check the gravity of the decanted solution with a hydrometer to confirm fermentation.

 

[doug293cz]

Sixteen hours is not an overly long time to have a starter on the stir plate. It might or might not be done. Turn the stir plate off for three hours, then give it a couple of good swirls for aeration. If you get an instant krausen, it is not done. Shaking it will give you some foam, that looks like krausen, but foam will dissipate rapidly.

I do something similar: turn the stir plate off for a while, and then just turn it back on. If it foams up, then active fermentation is occurring. If a yeast cake is forming on the bottom, but it doesn't foam when turned back on, then the starter is pretty much done. A three hour wait seems excessive. I've found 15 - 30 minutes to be enough. The krausen after three hours might overflow the beaker.

Brew on