What is this film on my beer? :-(

[robertandrews]

I just opened my fermenter after one month to find this film on top...

I had planned on bottling this tomorrow.

Beer is a winter warmer I tweaked (http://urly.fi/aIN) based on Holiday Prowler (http://urly.fi/aIO) - combination of light, crystal chocolate grains, plus beer enhancer and, if I remember correctly, dark spraymalt.

-- Brew day was Nov 10, OG @ 1.046

-- Reading taken Nov 17 @ 1.020 (all looked great)

-- Discovery - Dec 7 @ 1.010

Film is thin, almost powdery dry, breaks easily. Beer underneath looks good and brown.

What has happened? Please don't tell me this is mouldy and ruined.
I have removed the film. Tasted a small amount of beer from beneath the film; didn't taste off (but what am I looking to taste in an infected beer?).

The one thing I could point to, speculatively, is air. No bubbles ever emerged from airlock, only from between the grommet and the fermenter lid, and only audibly when the lid was pushed. This fermenter from Wilkinson, came without a hole of its own; one needed drilling in. Between brew day and reading one week later, I opened fermenter manually to inspect and photograph, then not opened again for three weeks.

NB. I sterilised the boiling cauldron, fermenter etc with boiled water and steriliser.

 

[Trox]

It looks like a lacto infection, but from what I understand if you carefully rack from under it, it should be safe to bottle and will still taste good.

Here is a thread that you can use as a comparison to what you have:

https://www.homebrewtalk.com/f39/post-your-infection-71400/index153.html



Others in that thread said they were able to save their beers from this type of infection.

 

[Yooper]

I'm not good with identifying infections, but it looks like lacto (or brettanomyces) from the photo.

It's probably from a long time in the fermenter with a wide headspace from being in a bucket. I know lots of folks talk about leaving their beer in the fermenter for a lengthy period of time like that, but that is one of the risks when the brew is in a bucket and the bucket's been opened.

 

[Brewskii]

Search the term "pellicle".

This is an infection. Won't hurt you but that beer is not going to taste very good. These microbes are persistent so, you may want to consider getting rid of that plastic fermenter.
Review your sanitation procedures. Could have come from anything introduced after the boil. Vinyl tubing has been a weak spot for me. I boil it before and after each brew and replace it often.
P.S. people wil tell you to not dump it and let it go as a sour beer. You could do this but, in my opinion, it still isn't going to taste very good.

EDIT; if you were going to keep it as a sour, removing or breaking the pellicle is bad form. Air will do bad things Ive heard and leaving the filmy top on helps protect against this. I don't do sours so I can't help much more than that.

 

[robertandrews]

FYI, I've bottled this today, one day after the above discovery.
Beer tastes fine, no hint of vinegar. Hope it stays that way.

 

[krackin]

You left your hydrometer in the bucket didn't you? It has krausen all over it. Don't do that, it will bob up and down with temp and fermentation changes and potentially help introduce unwanted participants.

 

[chris9be]

Hi, was this beer fine in the end? Just got this same film on mine!

 

[chris9be]

Hi, was this beer fine in the end? Just got this same film on mine! I know this is very old...hopeful of a reply

 

[pvpeacock]

I had a few infections in a row a number of years ago with pellicles like that (before I discovered the cause). I kegged all of the batches and let them condition. One was one of best beers I have ever made. One was so awful, I had to dump all 5 gallons. The third was okay (a stout) after aging about a year, but nothing special. You just never know.

 

[Snuffy]

They pay extra for that in Belgium.

 

[Ninoid]

I have had this infection a few times and each time the beer was fine, but I racked it from the bottom, making sure to leave a few centimeters of the surface layer in the fermenter. Afterwards, I disinfected the plastic fermenter with undiluted bleach, washed it well with hot water and left it open for a few days to evaporate the bleach smell, and then disinfected it with Starsan. If this infection starts to occur more often, the fermenter should be thrown away.