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Lambic beers are a Belgian specialty which is still made by open-air "inoculation" by airborne microbiota first, followed by additional yeasts, LAB bacteria and more joining in at the time of transferring to used wine barrels. (No yeast is "pitched" or added intentionally.) As many as 200 organisms may play a role, and they seem to take turns, partly regulated by rising acidity and alcohol probably, but with some such as Brettanomyces seeming to simply wait their turn compared to what they will do in a single strain fermentation.

Lambic (or American Coolship Ale hereabouts) fementations can take up to 3 years. Often a thick fluffy "pellicle" or "film" forms on the top of the barrel, like "flor" on sherry, evidently in response to and protection from oxygen. (Sure seems like a bio film.)

(There have been a few studies tracking the staggered blooms of various organisms, including one done 2 years ago at Allagash and one this year at Cantillon, but no discussion about how the sequence is orchestrated. So this is a speculative question about the evolution of these beers.)

Could interspecies quorum sensing be at work? How could that be confirmed?

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  • $\begingroup$ First it is important to identify the species that co-habit the fermenting malt. $\endgroup$ – WYSIWYG Jun 4 '14 at 11:04
  • $\begingroup$ That's the part that's been done. (The numbers of different yeasts and bacteria are high.Each fermentation allows wind borne contributions and differing communities in second use barrels, so there are differences between batches.) Actually, I just thought of something from watching a Bonnie Basler video: Could anything be learned by looking for one of the sensing molecules? And found a paper about Acyl homoserine lactones found on surfaces in a modern brewery not trying for ambient brewing. I so want to state that these fermentations are timed by Quorum Sensing. Almost certainly, right? $\endgroup$ – gail with questions Jun 4 '14 at 17:21
  • $\begingroup$ can you add that information. What are these microbes? $\endgroup$ – WYSIWYG Jun 4 '14 at 17:49
  • $\begingroup$ ok, two studies. The newest one, which I am struggling to grasp, is ncbi.nlm.nih.gov/pmc/articles/PMC3991685 $\endgroup$ – gail with questions Jun 5 '14 at 2:20
  • $\begingroup$ That Belgian study showed "diverse members of the Enterobacteriaceae" (month 1), Saccharomyces cerevisiae and S. pastorianus (mos 1-3) then Saccharomyces spp. decreases and Pediococcus damnosus increases from 3 mos, followed by highly acid- and ethanol-resistant Dekkera bruxellensis, (aka Brett) which dominated from 6 mos onwards together with P. damnosus. (plus N. castellii, Hanseniaspora spp, Kazachstania spp, Acetobacter spp, Etc.) The earlier study, from the US: ncbi.nlm.nih.gov/pmc/articles/PMC3329477 $\endgroup$ – gail with questions Jun 5 '14 at 2:39
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Almost certainly not. Species occupy different niches due to their differing growth rates and tolerances. Interspecies quorum sensing and the symbiotic relationship that implies do exist(see: lichen), but open-air inoculation is unlikely to produce them.

Why would the Brettanomyces simply kill time waiting for 'their turn'? It's likely they don't grow as fast as S. cervisiae or other early fermenters, and as a result they're outcompeted until alcohol content rises enough to slow or stop other species. Brettanomyces isn't 'waiting', they're eating and growing as fast as they possibly can.

Many microorganisms form spores or simply hibernate until conditions are favorable for growth. For highly acid and alcohol-tolerant species, perhaps they sporulate until the mix is acidic enough to guarantee them habitat. This is a form of quorum sensing, but the transmission medium is pH and alcohol concentration.

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