I was wondering…is there a way to visually determine pellicle identity besides applying a microscope?
There seem to be several common visual types of pellicle going around, rangin from a flat surface skin, to more alien white balloony bubbles, all the way to colourful ridges. Are they all the same organism(s) or does each mibrobe and strain have its own pellicular characteristics?
Any literature available on pellicles?
Michael Tonsmeire mentions in his American Sour Beers how several commercial sour beer brewers visually inspect the pellicles on the ageing beers in their barrels. Maybe we’re only just in the stage of pragmatic empirical practice, rather than hard-boiled science…
The difference between a flat pellicle and the white balloony bubbles are only bubbles. If there is no off-gassing then bubbles do not form in the pellicle and the pellicle stays flat. I have not observed colorful ridges. I have not seen differences in pellicle between lacto and Brett. My 2 cents.
The only things you can identify with any accuracy by looking at the pellicle is how well it is covering the top of the beer and whether there is any mold growth on it (which is extremely rare).
I’ve done several brett-only beers and their pellicles look identical to pellicles in beer with both brett and lactic acid bacteria.
I’m not entirely sure what causes different thickness or opaqueness in pellicles but I suspect a major contributing factor is the extent of oxygen exposure as the primary purpose of a pellicle is regulating exposure of the beer to air (and competing species that might fall into the food source).