Spontaneous fermentation experiment gone "wrong." Now what?

[JustinG]

I've never brewed any sour beers, and I had no plans to for the immediate future, but last weekend (4 days ago) I brewed a 1bbl batch of a session IPA and ended up with 1 gallon of wort afterward. My plan was to take this and boil it with 2 gallons of unhopped wort (50/50 light/wheat DME) to make 3 gallons of relatively-low IBU wort and then leave it in my backyard for a while and see what kind of local yeasts I can pick up.

The problem is that, due to several scheduling issues, I was unable to pick up the DME until this afternoon, so the wort was just sitting on my kitchen counter in a large erlenmeyer flask at 76F ambient (covered tightly with aluminum foil and with a towel around it to protect from UV exposure). It looked like there were a few tiny mold spores forming yesterday, but other than that, it didn't seem to be doing much.

Fast-forward to today: I finally got the DME and figured I'd get this done and set out this evening, but when I took the cover off the flask, I found it to be in high krausen, fermenting away.

So the problem now (besides having a gross base beer with a 4-day lag time from cooling to fermenting) is that I have 1 gallon already fermenting with what I would suspect is saccharomyces (the flask, although cleaned, previously contained Safale S-04). If I boil the other 2 gallons, chill, and blend together, won't the saccharomyces just ferment the rest of it, without giving other yeasts a chance to compete? What are my options now?

The only thing I can think of is to let this current beer finish and just do the 2 gallons of unhopped wheat beer separately, and hold the first beer in secondary while I wait for the other beer to take off with wild yeasts. Then I could blend them together, which would presumably allow the original beer to undergo a second fermentation (assuming that I get some sort of brettanomyces or the like from the wild fermentation). Is this the best option?

What would happen if I just added the new wort to the already-fermenting first beer? Would I just get a gross beer fermented with what I assume is saccharomyces? Or will I still have a shot at getting some other bugs in there if I let it ferment open outside?

Sorry for the length, and thanks in advance!

 

[GilaMinumBeer]

Well, sounds like the spontaneous bit took. What makes you think leaving it open would be any less gross than what you have now?

And, adding wort to fermenting beer is, essentially, Krausening. You just aren't adding it for carbonation.

IIRC, Bass was founded on a system of adding fresh wort to fermenting wort as a continuous production method.

 

[JustinG]

Sure, I know it will take right off if I add the wort to the fermenting beer, but my original goal was to ferment this with local wild yeasts, rather than saccharomyces alone. If I add it the wort now, I'll just end up with a standard sacch. fermentation (assuming that's what I've got in there, which seems to be the case, judging by the look and smell of it).

The reason I think it would be more "gross" is simply because this is bound to taste like a weak, estery (76F temp with S-04) pale ale that sat out for 4 days before it finally started fermentation. I was hoping that a spontaneous fermentation with various wild yeasts and other bugs would give it an interesting character; at the very least, I'd be able to get an idea of what the local wild yeast is like.

 

[GilaMinumBeer]

Just for clarification, are you of the camp that boils your starters in flask?

If yes, then what makes you think it's sacc?

If no, then, you might need to start over.

 

[JustinG]

No, the flask was used to rehydrate the S-04 that was used in the large batch. There was a full gallon of good wort left over after transferring to the fermenter, so the flask was cleaned, filled with the gallon of extra wort, and covered in foil. That's the one that's fermenting now.

 

[broadbill]

Sure, I know it will take right off if I add the wort to the fermenting beer, but my original goal was to ferment this with local wild yeasts, rather than saccharomyces alone.

If this is your goal, you have missed your window to do this; whatever is in there is already going...

At this point I think you are at a keep or throw away decision point.

 

[levifunk]

So lets assume the flask had S-04 in it and that is what is fermenting currently. You could pasteurize that portion, add it to the other 2 gallons, and then try a spontaneous fermentation. There will still be plenty of sugars in the other 2 gallons to allow for the wild yeast to ferment.

Some problems with this are that you are using a very low hopped wort to pick up wild bugs in air that is abundant with bacteria this time of year. Risk of bad bacteria taking over is high.

 

[chad_]

Also, you could take a taste test of the bit thats fermenting, if it tastes odd it is probably wild yeast. Also note that if you do create a wild beer and it is sour, it make take upwards of over a year to actually taste like a good sour. So don't throw it away if it has a bed sour taste, just put it somewhere and forget about it for a year.

 

[JustinG]

So lets assume the flask had S-04 in it and that is what is fermenting currently. You could pasteurize that portion, add it to the other 2 gallons, and then try a spontaneous fermentation. There will still be plenty of sugars in the other 2 gallons to allow for the wild yeast to ferment.

Some problems with this are that you are using a very low hopped wort to pick up wild bugs in air that is abundant with bacteria this time of year. Risk of bad bacteria taking over is high.

This is an interesting option. Would pasteurizing the fermented batch burn off the alcohol in solution? If not, will the alcohol already present inhibit fermentation from wild yeasts? As far as the hops comment goes, I can add some hops to the new wort if needed, but unfortunately I don't have any truly stale hops. The beer that already ended up fermenting with (probably) S-04 was about 50IBU; do you think this will have an impact? If simply adding old but not stale hops, how much do you think I should add to 2 gallons of 1.048-ish wort to inhibit bacteria growth?

 

[levifunk]

No, it won't burn off the alcohol. Depending on what temp you pasteurize at, theoretically some alcohol may evaporate, but if you've ever distilled, you'd know it takes a LONG time.

I don't know how much hops to add. Go to your local homebrew shop and ask if they have any old hops. Most places have some. I'd hop it up as much as you think you can tolerate. Bacteria level in August in Florida have to be pretty high...