Is My Yeast Starter Dead?

[DanMurphy]

Hi, I'm a semi-noob who has made a few batches of extract-based "beer clones" from Adventures In Homebrewing. This time, I decided I would try my next batch (also from AIH) using a yeast starter. I got a yeast starter kit consisting of a Erlenmeyer flask, electric stirrer plate and some DME. In the process of boiling the wort on the stove I managed a "boil-over" and lost some that way. I then cooled it down and added it to the flask and added the White Labs liquid yeast (which I had kept in the fridge for the few weeks since I received it). I then capped it with a stopper and airlock. It has been agitating for 48 hours now and has grown a layer of foam, but I haven't seen any bubbles coming out of the airlock. I don't know if the starter is any good, how can I tell? Could losing some wort to the boil-over have affected the yeast? I did sanitize every container and tool that came in contact with yeast beforehand. I am a little paranoid about starting a batch of beer with dead yeast, but have know way of knowing if I should toss the starter and begin again. Here is my setup.

 

[passedpawn]

That foam is the krausen. It means your yeast is quite active. Pitch that yeast into the wort.

I don't know why you didn't see bubbles in your airlock. Certainly, a ton of CO2 was produced. There must be a leak somewhere.

BTW, next time don't put an airlock on that flask. Use a loose piece of foil. You really want air to get to that starter. It will maximize the yeast production. Of course, you don't want bacteria in there, but bacteria doesn't fly, so as long as you've covered the flask, you're good. Fruit flies can be a concern. You can buy foam stoppers that allow air through but not flies. They are really ideal I think (I never had one though).

 

[Jwin]

That is a very small starter.
Tip, use fermacap for you starter boil.
Turn off your stir plate for an hour or two.
You will see the yeast settle to the bottom some.
That's what has been populated.
Happy brewing.

 

[Qhrumphf]

Starters need oxygen access for yeast growth. Using an airlock eliminates that oxygen access, and makes using a stir plate totally pointless, as after the yeast scavage all the oxygen in the flask, all the stirring in the world won't help them. Foil is good, foam is (likely) better. Injecting fresh air (NOT pure O2) into the headspace while on the stir plate is best.

http://braukaiser.com/blog/blog/2013/03/19/access-to-air-and-its-effect-on-yeast-growth-in-starters/

 

[bobeer]

That starter looks good to me!

I just made a starter out of some yeast I had bought 2 Augusts ago. It took 3 days to get going but it's there now. Sometimes, if you don't see any activity, you just have to wait it out.

Good luck with your brew!