A few weeks ago I asked about jazzing up my Berliner Weisse, which hadn't gotten very sour. After hemming and hawing over what I wanted to do, I decided to add apricot puree because I happened to find myself in a store where it was for sale. When I went to add it last week, I noticed a thin pellicle had formed. Q1: Does lactobacillus form pellicles? I used whitelabs lacto strain, but I'm guessing there is an unintentional source of contamination at play here. I sanitized a bucket that I had previously used for sours, with Roeseleare yeast, so maybe that is the source. Back to my story, despite the thin pellicle, I ended up adding the apricot directly to the primary, and I opened the bucket today to see how sour it had gotten, and the pellicle was rather impressive, and now with bits of fruit mixed in. https://www.dropbox.com/s/k0i91w8en8zq4mj/Apricot Sour Pellicle.JPG?dl=0 I sampled through the pellicle to see how much sourness was added (noticeable). Q2: Should I keep the brew in the bucket? Now that I have this big mess in my fermenter, I'm inclined to leave it there for a while. But I do wonder if I'm going to just oxidize everything because its in a bucket. I realize the pellicle can help keep out oxygen, but will it be enough if I don't disturb it? Recommendations welcome.
I'd let it go for a little while. Depending on how much you open it, and how long you plan to keep it, it might not pick up much of any acetic character. If it seems like it is, I'd move it, but I'd be inclined at the moment to leave it alone. And yes, Lacto can make a pellicle.
I think you're good; the observations above seem accurate. The lacto will consume some oxygen so you'll probably be fine for now. Just don't leave it in the bucket for a year...
Like the others said, lactobacillus can and obviously does form a pellicle. Keeping in a bucket for a long time can cause oxidation; the plastic does allow oxygen through it, although very slowly. The one thing that hasn't been mentioned is that you should not use this bucket for any 'regular' brews - the lacto can get into the micro-scratches and is almost impossible to completely sanitize.
The bucket has been dedicated to beers with bugs and has seen a few Brett fans lacto fermentations. Since I had never seen a pellicle from an all-lacto fermentation, I thought I could be seeing evidence of contamination from an earlier funked up batch. I was actually sort if hoping that something interesting was going on .., But my oxidation concerns go back to a previous sour that did go to cardboard on me when my seal on my better bottle was discovered to be loose after several months,
