Collected a couple gallons recently from a high gravity brew session to use as a yeast starter. Never got around to actually pitching the yeast so the wort sat around outside for a couple of weeks covered in foil. I decided to wait and see what happened and it started showing signs of fermentation this weekend. Its at high krausen now, and it smells actually pretty awesome! Kind of reminds me of a saison.
I’m going to let it ferment to completion and if it turns out half way decent I may use it for a saison in the next few weeks.
My previous attempts have been awful as well. I’m starting to wonder if some residual yeast didn’t carry over from a previous starter. This smells way too clean.
We have a club member here in the Northern Chicago suburbs who did a similar experiment and produced 5 gallons of beer with a “spontaneous” yeast cultured from a dish of wort left in the backyard. The results were interesting. I asked a friend who is a professor of microbiology about this type of experiment and she advised that there are a number of pathogenic organisms that can ferment a sugary liquid besides yeast. Her basic advice was that it might simply be yeast, but it also could be something that could make you very sick or even kill you. If it’s somewhere in between, you might serve the beer with a caveat that anyone who has a somewhat compromised immune system might not want to try your “experimental” brew. I have decided that its pretty difficult asking people about the status of their immune system when I am serving them beer.
I tend to be more cautious with these types of experiments, and use commercial cultures for all of my sour beer experiments simply because I feel safer knowing exactly what is in my beer.
Yeah, I’m not worried about any harmful organism surviving the fermentation. If that was the case the human race would have died off millions of years ago. For thousands of years beer has been safer to drink than water, for a reason.
Microbiologists are paranoid. I’m not saying it can’t happen, but they tend to see infection everywhere. Much like my oncologist/radiation therapist friends see cancer everywhere…
Given the history of spontaneous fermentation, I’d be more concerned about the beer tasting like crap than killing you.
BTW, that is definitely a yeast fermentation going on there. Bacteria fermentations do not look anything like a yeast fermentation. Not saying something else isn’t probably swimming around in there, though.
Also, while we are on the topic, there are still breweries doing spontaneous fermentation today.
Some of the wort stability tests I have done in the past ended up as yeast fermentation while others were bacteria fermentations. I as I see it, yeast is naturally a large source of contamination in any brewery.
In my old club, we had a barrel experiment that soured unexpectedly. Since I had access to the micro lab at the time, we plated the beer, cultured what came out of it, and found a strep bacteria as well as another spore forming bacteria. Ultimately we came to the conclusion that one of the bacteria probably came as a result from an individual mouth siphoning. According to the same micro professor, they were both known human pathogens, and though they were not especially harmful to a healthy individual they could potentially be harmful to someone with a distressed immune system.
Gross. Still, I have a hard time believing that anything harmful could live in beer. If this were the case people would be getting sick all the time and beer would not be a stable product. Not saying your wrong, just saying it goes against the evidence.
Already fermented beer with hops is resistant to other microbes. Wort before the yeast have a chance to build a colony is sugar water waiting for bugs to come eat it.
Don’t forget that yeast product alcohol which is a disinfectant. When Alch gets high enough it starts killing those nasty critters but the yeast can still tolerate. That’s one reason a quick start to a fermentation is desirable, to keep the weak and infirmed at bay.
Keep in mind that theres a difference between wort and beer. If you culture something from your backyard and put it in 5 gallons of wort, it may or may not become beer.
Isn’t everything in life potentially harmful to someone with a distressed immune system? I’m supposed to give up my dream of fermenting with elephant dung to appease these people??
