Small white growth? On the side of flask of saved yeast

[zman_]

I have a vial of yeast that I saved from an overbuilt starter and was looking at it today and noticed a small white speck on the side exposed to the air (above were the wort is covering). Is this something I should be concerned about?

Additionally, I noticed that the yeast layer on the bottom was a bit bumpy rather than smooth like expected.

Unfortunately no pictures as of now as I stupidly agitated the flask trying to get a better look at it.

Any help is appreciated!

 

[mmlipps]

I'd be cautious, mold is a bit**

 

[Calder]

I'm sure everyone will recommend tossing it and not using it ...... not worth the gamble with the cost of a whole brew.

But ... if it were me, I think I'd hate the though of wasting it and would take the risk. I'd make a starter (with a hop pellet), and taste the fermented starter wort for any sourness or other obvious off-flavor, and use it if it were good.

If I thought it was compromised somehow, I would not be planning on using it for multiple brews.

 

[mmlipps]

How old is it?

 

[lumpher]

I'd be worried it's mold, if I were in your shoes. NFW would I use it.

 

[zman_]

It is approximately 2 weeks old. The jar was previously autoclaved before I used it, starter wort was boiled for ~15 min. Jar + lid was completely submerged in starsan for several minutes before being shaken/dumped out/filled, pushing out almost all the foam.

My main worry is that it would be mold and I obviously don't want that to get into any beer/etc, and tossing it/starting over isnt a huge expense, but obviously, would rather not have to.

 

[zman_]

Ended up tossing it this morning. Wasn't looking good as it settled and it's not worth the risk to save a small amount of money. Guess I will just have to be even more careful the next time I try to save yeast

 

[mmlipps]

Quality Assurance

 

[zman_]

Now its time to autoclave all my glassware over the weekend!

 

[CUrchin]

Right move... Not worth losing a batch over.

 

[zman_]

The only thing I am wondering is how to best prevent this in any future batches. The only places I could ID weaknesses in my sanitation/etc is that I wasn't wearing gloves during the process (despite avoiding contact with any liquid/sanitary surfaces), that I didn't CO2 purge the receiving vessel for my ~100B cells off the overbuilt starter, and that there was ~1" of headspace in the flask I was using. I guess I will just have to try CO2 purging the flask, and top it up the whole way, and ensure that I am wearing gloves whenever I am handling things on the clean/cold side (which I normally do during the brew day).