Is my yeast starter okay to pitch?

[strange_design]

I made a yeast starter and didn't touch it for a couple of days. I took the plastic bag I had wrapped around the mouth of the growler I was using to cover. I forgot to wrap it around the mouth, only covered the growler. As I took the dog for a walk, some fruit flies got inside the bag that covered the growler. I replaced the bag and put the growler in the fridge overnight. I decanted in a bowl this morning and inspected the yeast: no flies in either. What's your verdict?

 

[Pratzie]

U don't wanna let it go for a couple days. Shake it periodically (if ur not using a stirplate) and pitch it within 24 hours.

Also, use foil, it'll leave a loose seal, letting the CO2 vent out, some oxygen in, but it'll keep the bad stuff out.

 

[bzwyatt]

I kind don't get your description of where the flies got to - justs inside a bag that surrounded your container holding the starter? Seems like the starter might be ok... but if it was me, I'd rather lose the starter than risk losing a batch of beer, so I'd get new yeast.

 

[strange_design]

Sorry, I should have been more clear. The flies were just on the inside of the plastic bag that covered the growler, I have not found any inside the starter itself.

 

[strange_design]

-double post-

 

[flars]

If you were making the starter, not using a stir plate, it is most likely not finished. Making a starter by the intermittent shaking methods means shaking the starter container as often as possible to add oxygen for the yeast to work with. Each time you shake the container a krausen will immediately form. When this no longer happens the yeast have finished their work.

 

[strange_design]

The krausen had fallen already and it had been over 48 hours since I pitched the yeast in the starter wort in the growler, so surely it was finished? My main concern is the fruit flies that got inside the plastic bag covering the growler but not necessarily in the growler (hard to believe but I checked thoroughly for floating fruit flies).