- Nov 2, 2019
- Reaction score
The film in this case is a pellicle. It indicates the presence of wild yeast and/or bacteria, and oxygen in the headspace.
That's what I thought. I got the "light version" of it. The longer I keep the beer in my fermenter the higher the probability that this film shows up (in a very thin form).The film in this case is a pellicle. It indicates the presence of wild yeast and/or bacteria, and oxygen in the headspace.
I wouldn't describe a pellicle as "oily". You can see in the photo it does not reflect light at all; at the bottom of the photo we see light reflecting from a little bit of exposed liquid, but not the film. A pellicle is generally more thin and always more hydrophilic than coagulated fats, and forms more jagged shapes or simply covers the whole surface.
Unless you're intending to use wild microbes, you're experiencing a recurring contamination. Also, there's oxygen in the headspace because the microbes typically won't form a pellicle otherwise.