what is this film/ dots on my cider?

[Zwegert]

I reracked my cider for the first time and after a month this Film just started to form on the top with some white spots in addition (the dark spots on the picture are from my broken camera).
What should I do with this?
Label it off and just bottle it as planned? Tasted some out the bottom valve, no off flavors but tasted different from before the reracking, more tart but not sour. Could it be starting to turn into vinegar?
Thanks in advance.

 

[JohnSand]

Welcome aboard!
I've only made cider once. I bottled after the initial ferment, and didn't have spots on it. One portion I fermented naturally, with only the yeast already present in the cider. That part was much more tart than the others. I suspect lactobacillus.

 

[SouthCountryMom]

I reracked my cider for the first time and after a month this Film just started to form on the top with some white spots in addition (the dark spots on the picture are from my broken camera).
What should I do with this?
Label it off and just bottle it as planned? Tasted some out the bottom valve, no off flavors but tasted different from before the reracking, more tart but not sour. Could it be starting to turn into vinegar?
Thanks in advance.

My apple cider vinegar (my first attempt!) has done this. The film is tough with bubbles you can chase around but not pop. Have you found out what it is? Have a good one!

 

[D the Catastrophist]

Probably a pellicle.

https://brewingforward.com/wiki/Pellicle#:~:text=A pellicle is a film,(never fuzzy or hairy).
"pellicle formation is normal for fermentations that contain wild microbes or non-Saccharomyces cultures such as Brettanomyces.[7] For example, a pellicle frequently forms in mixed-fermentation beers, kombucha, vinegar, and wines, ciders, and meads with Brettanomyces or unpasteurized raw ingredients such as fruit or honey. The appearance of a pellicle in these products doesn't reflect what may be happening during fermentation with regard to quality or progress, it merely indicates the presence of the microbes"

 

[D the Catastrophist]

And no, a pellicle is not toxic or a sign you need to toss the batch. It actually has a positive trait-reducing oxygenation.

https://pricklycider.com/2021/07/21/film-yeast-flor-pellicle/
"Is it harmful? No. Does it mean your hard cider is ruined? No. Is it desirable? Maybe. This is actually your cider protecting itself. This film or flor creates a barrier that limits the additional exposure of your cider to oxygen. It’s also a method used in the production of certain wines. For example, sherry is made by aging wine in oak barrels that are partially filled and have a loose bung in the barrel."