Saved yeast infected???

Hello all. I save some yeast from 2 different batches a few weeks ago and am going to do a batch tonight. Both of the lids on the jars have a dimple on top and hissed a little when I opended them. I shook the yeast up to mix and when I opened the lid it foamed. Still smells like beer and yeast, nothing nasty. Both yeast had some sulfer smells so I am sure some co2 was trapped in them. Safe to use or chuck it??

The dimple should just be from the air volume cooling off and contracting from refrigeration. The hiss was most likely from the vacuum. I'd use it.

The dimple was out not in ..sorry..not a dimple more of a pimple

hhmm.. that means there was pressure not a vacuum inside. I wouldn't risk it then.

How did you save your yeast, did you wash them or did you just collect some of the slurry? If its just some of the slurry, its possible that the yeast had a little bit of extra time and were able to ferment a little bit of the beer that you brought with them, creating a little bit of CO2. That could also explain the sulfur smells, depending on the yeast. I'm picturing the whitelabs vials, I've had some of them foam up and hiss when I opened them and they weren't contaminated.

Of course, the other option is that they are contaminated, and its up to you to figure out if you want to give them a shot and risk the batch. Personally if it still looked like yeast and smelled like yeast (or at least smelled like yeast fermentation, which can be stinky), I'd go ahead and run with it.

Yep just slurry...gonna try it