2 likesIt's very difficult to identify the specific bacterial strain from a pellicle photo, it could be a half dozen different bacteria. Can you describe the smell? Is it more acetic than usual? Do you smell any rancid, butter, body odor, or vomit? Any slime or ropiness if you stir closely below the surface? Just keep an eye on it and see if it begins to appear to be a mold, in which case remove it. I intentionally pitch specific strains of non-yeast bacteria in my rum fermentations to encourage specific ester formation, and I'm starting to work on mixed culture whiskey fermentations, with very good results. There are a handful of lactobacillus strains that I absolutely adore in whiskey and rum. Yes, I said that, and yes I intentionally "infect" fermentations. Every whiskey fermentation that doesn't boil after mashing is "infected" with numerous strains of bacteria. Grain is incredibly filthy from a microbiological perspective. Even some strains of Streptococcus can survive lower-temperature cereal mashes. Same for the rum distilleries, just a different set of bugs. In addition, you'll develop your own mix of strains that define your house/colonial bacteria profile. What I do is force a specific profile to match the outcome I am looking for. Let it ferment out, run it, it may be the most interesting rum you've made. Here are two of my favorite papers on the prevalence of specific bacterial strains in whiskey distilleries: http://www.microbiologyresearch.org/docserver/fulltext/micro/147/4/1471007a.pdf?expires=1483011394&id=id&accname=guest&checksum=3F2159A77F8BCEB870E570C224754586 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC126549/ And Rum: http://onlinelibrary.wiley.com/store/10.1046/j.1365-2672.1998.00380.x/asset/j.1365-2672.1998.00380.x.pdf?v=1&t=ixabpopp&s=5841ec634998983c0b050add5b2dbeba52bd555c
1 likeYeah definitely sterilize a few containers and keep samples, if the result is great you are going to kick yourself for not attempting to culture it. I think there are lots of clues on the specific bacteria in the late heads. Typical acetic strains will just result in a larger than usual heads cut, nothing particularly interesting. But strains that generate higher amounts of butyric and propionic acid esters are where it's at - you'll get these in the late heads. Propionic and butyric esters - tropical fruit, bubble gum, rummy, pineapple, strawberry, apple, etc. Low acetic lacto strains are harder to pick out, slightly pineapple in the late heads, but without the juicy-fruit gum, slightly buttery early tails - but broadly contribute to the buttery/rich descriptor, absolutely - creamy, caramel, buttery, nutty.