White green stuff on carboy walls

[Rob M]

Racked a rye pale ale last night (controlled fermentation chamber and cold crashed 3 days) and found this stuff behind on the carboy and attached to the auto siphon. I can't find any other example like this stuff. Btw...smelled 'ok' but dry hopped at 4 days with Mosaic/Amarillo so may have masked the nasty a little. Wasn't as citrusy/fresh as expected.

 

[RPh_Guy]

It's a pellicle (film), not mold.

Your batch had some wild yeast and/or bacteria...
It's not dangerous. We can't determine which microbe(s) is/are present without sending it to a lab.

If you bottle condition, keep a close eye on carbonation level.

Clean your equipment thoroughly.

 

[Rob M]

It's a pellicle (film), not mold.

Your batch had some wild yeast and/or bacteria...
It's not dangerous. We can't determine which microbe(s) is/are present without sending it to a lab.

If you bottle condition, keep a close eye on carbonation level.

Clean your equipment thoroughly.

Thank you. A local microbrew owner I know suggested the same. So I may have a sour pale ale on my hands. Interesting. Never thought to save a sample for analysis. I'll up the cleaning/sterilization detail.

 

[RPh_Guy]

I assume you packaged it in bottles or a keg. Sounds like a sample to me.

There's a good chance there won't be any off-flavors (e.g. sourness) or any other issues.

If you can take any steps to reduce oxygen exposure post-fermentation, that'll help tremendously for all your brews. (A pellicle also indicates the presence of oxygen.)

Best of luck!

 

[Rob M]

Kegged. I fill my kegs with StarSan solution and then fill with CO2 pushing solution and try to not disturb the CO2 cover much as I rack to keg. Then I fill with CO2. Then purge all "air" to be safe and CO2 again. I still experience some oxidization. More noticeable with highly dry hopped NEIPA's.