I have a batch of cider that was in fermentation for several months. I use glass demijohns and racked 3 times so the cider is very clear. It's been about 2 months since the last racking.

When I took the demijohn out for bottling I found some white film on the top. It was not there in the previous racking. I use a siphon so I wasn't too concerned of getting it into the bottles, and the cider actually tasted great.

After three days in bottles (with sugar added for carbonation) I see white film on the top of each of the bottles, and it seems more than what I had in the demijohn, and developed fast.

I'm usually very careful about sanitizing but can't rule out some contamination.

I've read a few posts about film on top of beer but I don't know if things are different with cider...

I'm thinking of giving the bottle a jolt before opening it and letting the foam drive the film out. But will it be safe to drink?

Here's how it looks... a closeup of the top of a standard 11-oz bottle.

White foam on top of cider

Edit: six days later, whatever it is does not grow any more. It seems to have captured some gas at the top at start and now it looks like film-covered bubbles.

Closeup from above, 9 days after bottling

side view, 9 days after bottling

  • You have a lot of head space, perhaps you should rack into a carboy that matches your batch volume? Commented Oct 4, 2017 at 7:53
  • This is a close-up of a bottle (330 cc). Editing to clarify. Commented Oct 4, 2017 at 9:25

2 Answers 2


Looks like a very clean pellicle, biofilm from a bacteria. Taste the cider, you may have something nice there. But it's probably not what you were expecting from yeast.

  • Thanks. It seems to continue growing... perhaps brought up with the bubbles. I will update on how it looks and how it tastes (when it comes to that, hopefully). Commented Oct 4, 2017 at 9:39

Google search tells me this is likely beer pellicle common with some bacterias used in fermentation and can actually prevent bad bacteria from entering at least that is my take from this: https://beerandbrewing.com/what-is-a-pellicle/

  • Please try to answer the OP question: "Will it be safe to drink?"
    – Philippe
    Commented Aug 27, 2020 at 19:05

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