Wild Yeast Fermentation

[Bizier]

I am currently mashing a high grav lager, with significant wasteage planned. You just inspired me to use my leftover wort for some spontaneous funk. Perhaps even jazz-funk.

 

[Mr. No-Tip]

I'd love to get some opinions on the safety of drinking a spontaneously fermented beer. I remember reading (I think somewhere here?) that you want to ensure that the beer is below a certain pH to avoid nasty bugs getting in there at the same time as the yeast. What I can't recall is when the pH matters. Is the issue that the pH must below throughout, or is it that when you drink the beer and the pH is below a certain level you can be pretty sure there's nothing nasty in there. Or am I way off?

I tried a spontaneus ferment with a couple litres of 1028 BerlinerWeiss wort. I left a chilled pot under my quince tree for about an hour until the sun started to cast on it, so I then left it in the kitchen for another hour and poured it into a little glass fermenter with an oztop.

It picked up in a couple days and krausened pretty hard:



I left it for another couple weeks to see if any kind of pellicle formed, but it did not (the white head you see above is from where I opened the lid to smell and C02 came out of solution). I decided to bottle it today. 3 PETs, one with 1 carb drop and 2 with 2. I had a smell and a small taste of a cooled non carbonated sample. Very sour, almost lemony. Not really acetic. I was pleasantly surprised considering suggestionsnthat you were likely to end up with pretty gross flavours, and the fact that I did this on a 30+ day.

I am not 100% confident these will carb. The oztop released some gas the first time I opened it a week ago but did not today - fermentation is definitely finished. Considering the small culture there mightn't be enough to carb. Time will tell.

Obviously I have this brew in mind with my safety question above. It was a pretty lightly hopped (though I did have about 60g of aged hops which hopefully helped) and very low grav beer.

 

[bingggo]

I feel I am missing something obvious but wouldn't the reason the OP's experiment tasted like brewing yeast be because of the brewing yeast in the trub he used?

 

[mje1980]

I dunno but i just don't think I could drink anything that fermented like that. I quite like funky beers, but there are all sorts of funky wort eating bugs readily available in pure form. At least you know what's going in there.

Actually, it's hard enough to control store bought funky bugs to start with, let alone "wild" yeast.

 

[manticle]

I feel I am missing something obvious but wouldn't the reason the OP's experiment tasted like brewing yeast be because of the brewing yeast in the trub he used?

I think you are missing something. Considering it was wort and trub mentioned in the OP, it is safe to assume the trub is made up of hop and protein debris post boil and has not been near any yeast.

It's also a post from 3 years ago.

However it is more than possible the OP's brewery is home to various S. cerevisae strains after yeasr of brewing and using them and one of these has fermented the wort so in a way, you're possibly half right.

 

[bingggo]

Oh, I thought trub was the layer of sediment after fermentation. Seems it gets used both ways.

 

[manticle]

It's a generic word for 'crap what settles at the bottom' and it can be pre and post fermentation.

Sorry for the wikipedia reference: http://en.wikipedia.org/wiki/Trub_(brewing)