I've seen Jester King give a lot of different explanations for their mixed culture that contradict. The only info I've seen repeated with any consistency came from their former head brewer who claimed to have put together the culture. I assume he would know best what is in it.
Their early saisons were just 3711. Their early sour beers were isolated lacto and brett from wort they left out at the brewery. Over time the 3711 culture became infected. Eventually they decided to steer into the skid and added their local lacto/brett to the 3711 along with dregs from Fantome and Cantillon (possibly others as well). This became their house culture for everything that isn't coolshipped.
interesting. I've become skeptical at all the success every brewery seems to have with a coolship and spontaneously fermented beers. Open air cooling and fermenting in fresh barrel seems like it would have an enormous incident of failure, yet so many breweries are claiming to be having great success with it. I dunno, not calling anyone a Bull***t artist or anything, just seems like the rates of failure should be higher.
I should clarify that their SPON beers are coolshipped and do not receive any help from their house culture. I heard/read they dump 20-25% of their coolshipped barrels so there is definitely a degree of failure in the process. However, it's the way beers were cooled until the advent of refrigeration and the way more than just lambic has been inoculated throughout history. The problem is not reaching fermentation but getting a good flavor out of the process. Blending goes a long way to make that possible.
That said, how many breweries out there have active coolship programs going on? I know many coolships are being installed around the country but I'm not aware of that many that have successfully produced beer yet.
Their house culture has some local elements to it--both intentionally and unintentionally--but it's also "local" to Soy and Brussels, Belgium. I'm not hateful that their house culture includes commercial strains and dregs from other brewers. It's true of my house cultures as well. I dislike that they sometimes refer to it as locally sourced when that's not really the case.