Exploding Yeast Starter...still ok to use?

Hey all -

I made my first 1000ml yeast starter last night (about 19 hours ago) to pitch to the wort I plan on brewing tonight, which will give it about a 24 hour life outside the smack pack and before pitching to my 5 gallon batch. Everything went fine when I made the starter. I didn’t use a stir plate but it got plenty of aeration that evening.

This morning when I left for work, I gave it a swirl but noticed that it had pretty much separated. The plan was to leave it alone until I got home and brewed my 5 gallon batch.

Someone at the house, trying to help me in the aerating effort, gave it a good swirl today and apparently it exploded and blew the foam stopper off. They said that not much escaped and the foam stopper was put back on. I said not to swirl any more. Do you think this yeast will still be ok to pitch tonight? Is it bad to “disrupt” the yeast like that? Thanks!

The yeast wouldn’t have any issues being disturbed like that, the only thing I’d worry about is what happened to the foam stopper when it came out, did it fall on the floor etc, was it clean when it was put back in? The only issue I think you could have is if the starter was contaminated. I don’t think it’s very likely but something to be aware of, and there’s not really a way for you to determine that by tonight. If it were me I’d pitch it, like I said I think you’ll be fine.

In the future you might consider making the starter a few days before you brew, and once it’s finished put it in the fridge for a day or 2 so you can decant the liquid and just pitch the yeast. Not a huge deal with only 1000ml but as you make bigger starters it’s definitely a good idea.

I’ll go ahead and pitch it tonight and see what happens. I’m going to try to find out what exactly happened with the stopper.

I didn’t know the starters would be okay for a few days. Next time I’ll try putting it in the fridge once it is finished. Thanks for this, it was very helpful!