My old Trois starter is sour?

[Beerswimmer]

Not sure if I have an infection or not. If it is I'll toss it, but wanted to see what you guys say.

I have an old jar of Trois washed yeast that I took out of the fridge to use in an IPA. As it started to warm it became visibly active and I had to crack the lid to release the pressure. When I poured out the liquid to put the yeast in the starter I tasted it and it was suuuuper sour. Is that OK? I'll be decanting and topping with new wort later today and will taste again. I've used this yeast many times and never had it be sour, but this yeast is around 5 months old.

 

[d3track]

Sour is bad

 

[Beerswimmer]

Sour is bad

Yeah, I'm just wondering if the yeast is still viable or if it's just going to be a huge lacto starter that I don't want??

 

[d3track]

Don't want, you'd be pitching bacteria at this point

 

[williamelvin]

I've only used it once, but my understanding is that WLP644 can produce acetic acid in the presence of oxygen. (Though I don't believe it's credited with producing enough to be really sour.) I'd add fresh wort before dumping it.

 

[Calder]

I've only used it once, but my understanding is that WLP644 can produce acetic acid in the presence of oxygen. (Though I don't believe it's credited with producing enough to be really sour.) I'd add fresh wort before dumping it.

Brett can do that, but this is not a brett yeast. All evidence points to it being a sacc yeast, despite the name.

I'd decant the liquid and use it in something hoppy to stunt any lacto growth, if that is what you have.