Reusing a wild culture

[G_robertus]

A little over two years ago I brewed a lambic-style beer that I inoculated with random bugs from the air and some bottle dregs (I'll refer to it as L1). After 10 months I transferred the beer off and pitched new wort (affectionately called L1jr), but when I sampled the new beer after 14 months the beer was surprisingly not sour. There is plenty of funk, but nearly no acidity or sourness. I've also added some of this initial beer to a newly brewed beer (L2) which has soured and does have plenty of character. However I also let this wort outside for a night and added some dregs, albeit not as much as in the first one. I also added some of L1 to an infected stout-solera, which is too sour almost, and a bunch of lager. The lager however hasn't soured either, but SG is at 0.996 and it is funky AF. The stout has soured at each iteration of adding and taking beer. I do have to say that lambics 1 and 2 are fermented in glass with a cork lid and airlock, but the stout and lager are in plastic. I'll have to check what type of plastic, but my guess is that the lager is fermented in PE.

My question: what is going on? Too little complex sugars, dextrins or starches? Too little oxygen (seems unlikely in the case of PE)? Did I wait to long with supplying my Lactobacillus or Pediococcus with new food? A combination of both? The new wort on the L1 cake was made using parti-gyle with extra grains. I don't remember at what temperature I steeped the extra grains, but it was pale ale malt with corn and rye (2:1:1; OG 1.040) in leftover runnigs from an American barleywine. The bastardised blend of L1 and L1jr is not a bad one and I'm considering just blending these two to make something palatable. Maybe add some L2 as well for extra flavour. Does anyone have any other suggestions? Is adding maltodextrin at this time still a viable option to try and force souring? L1jr is at 0.998 or something right now. Do I take the L and just rebrand as a funky Saison? Would fruit give potential for souring, or would the simple sugars just ferment out and leave no acidity? Do I need more bugs to try and get something going?

Other follow-up question: I was looking to reuse the cake of either L1 or L2 for souring another beer, but I'm not sure that would work still. I'm edging towards L2 and hoping it would still work. I'm

 

[Alan Reginato]

... lost. Yes, you're lost. 😂

They're too many variables and it isn't a exactly science.

If it's already funky enough, just add some acid and call it a sour. Or drink as it is.

Reuse the cake, just to see how things are going to be.

Cheers!

 

[sweetcell]

how many IBUs in the different beers?

some LAB is very hop-sensitive, anything more than single-digit IBUs and the LAB won't do a damn thing (main reason why brewers started using hops: it prevented beer from going sour, or it took a lot longer). if L1 was 5-10 IBUs, and L1jr was 20+ IBUs, then that might explain it.

other rando things you asked:
- adding maltodextrin might work, *if* your issue was lack of food for the bugs (L1jr at .998 isn't going to have much for LAB to munch on). but if the issue is high IBUs, then adding malto or any other food source isn't going to help
- fruit can add acidity, especially high-acid fruit such as raspberries. yeast and LAB will ferment the sugar but the fruit's acids will remain. but in my experience it's a small boost in acidity - note how a raspberry wheat ale isn't a sour
- brett & LAB are pretty resilient, so they're still in there, so you probably don't need to add more bugs. if your culture had never soured, then i'd say add new bugs - but since L1 soured up, the problem is unlikely to be the culture.

 

[G_robertus]

I did a WP with a tiny bit of magnum (1-6 grams, don't remember) because it felt weird doing it without any hops. I did calculate the IBUs beforehand and it should've been below 10 I think. After thinking some more on the subject I settled on an issue with nutrients. I added some of L1 to a milk stout that has closer to 30-40 IBU and that soured a lot, so I don't think hops are the problem. Probably the parti-gyle wort was very low in nutrients, as was what could've been left in the lager. I think I'm going to draw of some beer soon and either blend it with the old lambic or bottle as is and add (very) acidic fruit/vegetables to the new beer like rhubarb and maybe raspberry. That way it'll at least get some tartness even though it might not sour completely.

I decided to split up the new beer as well and added three different cultures to see whether any of them will sour the new project and hopefully I can blend from there. Thank you for the inputs though, as it did help me reflect and relax somewhat on the topic. I'll see what happens from here on and at worst it'll be a funky Saison that I might be able to blend into a host of other things.

 

[McMullan]

No. The different bugs colonise and establish in the wort in a predictable sequence. Like an ecological succession. Dumping them all in there at the start is unlikely to produce the same result, if that was the aim.

 

[G_robertus]

No. The different bugs colonise and establish in the wort in a predictable sequence. Like an ecological succession. Dumping them all in there at the start is unlikely to produce the same result, if that was the aim.

No, I definitely was not looking for the same result. I was aiming to pitch a mixed culture of which I know they can provide funk that I like together with sourness. The latter hasn't worked though.

 

[McMullan]

No, I definitely was not looking for the same result. I was aiming to pitch a mixed culture of which I know they can provide funk that I like together with sourness. The latter hasn't worked though.

I suspect the microbial community developed from ‘L1’ so that ‘L1jr’ was a different set of species. You created an artificial environment that selected against some of the microbes or changed their relative proportions. Mixed cultures can be very unstable in artificial environments like wort. Repitching is unlikely to work well.