Spontaneous Fermentation - Now What?

[FunkedOut]

Looks like you're about ready to grab a microscope and do some gram stains

Next step is a PCR and some electrophoresis gels to determine whether they actually were the same.

(Joking)
But seriously homebrewers have done it.

I’m starting to learn your sense of humor.

 

[MizzouFermentationScience]

Those 2 pennies don't jive in my mind.
I find it easier to get behind the I don't believe in commercial yeast mindset.
All the commercial guys have is wild yeast that's been captured, isolated and propagated.
I'm not sure what you're telling me here, but I'm listening...

I'm not saying I have a revolutionary future award winner here. It might be pure trash, but I am willing to explore this a bit and find out.
I feel like I have gotten very lucky this far, capturing a bug that produced fermentation that made a decent smelling and tasting beer.
Then streaking on a plate that is well suited to bacteria and not growing any?
OK, that one's a maybe.
On to the next step to keep on pushing my luck.

Here's a better pic of the plate:
View attachment 562258

I made up 5mL of 1.020 wort using distilled water and Pilsen Light DME.
Made the wort in this sanitized bottle I had from hot sauce adventures, then boiled the wort, uncovered in the microwave with 5 second blasts.
As soon as I saw a boil over starting, I hit cancel, put the sanitized cap on, and shook it a bit to do my best to sterilize the cap.
View attachment 562259

Once it cooled, I grabbed 3 isolated colonies with a sterilized loop and swirled them into the bottle, gave it a shake and back to the waiting game.

My comment of not believing in wild yeast refers to my belief that commercial strains are so strong and probably ubiquitous in a homebrewer’s house that my bet is that you probably caught a few cells of it and it out competed any wild yeast that may have been in the wort.

I work with wild yeast in wine, there is research that ~30 percent of even commercially inoculated fermentations end up with a different yeast (a “house” strain derived from commercial yeast that out competes any other wild or commercial strain eventually).

We are pretty crazy about sanitation but by the middle of harvest, uninoculated “wild” tanks start fermentation within hours- there is just so much inoculum in the air.

I fully support wild yeast (I call it spontaneous fermentation due to my suspicions). If you want to do some sweet science, have fun. I wouldn’t worry about safety, if it is fermenting and smells relatively normal, there is a very low chance of any ill effects.

I guess my take away would be, instead of isolating the culture (which I suspect is commercial) and pitching a full cell count, I would keep messing around with uninoculated wort. In wine, I consider the 3 days before 4% ABV critical to flavor development. Before a commercial strain fully takes over, the wild yeast eats sugar and does funky things. 99% of the microbes that come in on grapes will kill die when alcohol is produced, I consider time more important than strain.

 

[RPh_Guy]

My comment of not believing in wild yeast refers to my belief that commercial strains are so strong and probably ubiquitous in a homebrewer’s house that my bet is that you probably caught a few cells of it and it out competed any wild yeast that may have been in the wort.

I work with wild yeast in wine, there is research that ~30 percent of even commercially inoculated fermentations end up with a different yeast (a “house” strain derived from commercial yeast that out competes any other wild or commercial strain eventually).

We are pretty crazy about sanitation but by the middle of harvest, uninoculated “wild” tanks start fermentation within hours- there is just so much inoculum in the air....

There are things to consider when taking experience from winemaking and trying to apply it to brewing.

Wort is for practical purposes fully yeast-free before we think about pitching yeast. This gives wild yeast (collected away from the brewing environment) a clean slate to reproduce.
I'm guessing you don't sterilize your must before transferring it into sterile tanks. I recently read that fresh-pressed apple juice has around 100 Billion yeast cells per mL. These wild yeast cells have spent many many generations living on this fruit and having to fight for survival against the environment and other microbes, so it's really no surprise they can start fermentation so quickly. I'd think the press is basically impossible to fully sanitize so you'd also get hardy house strains growing there and inoculating everything you press.

The other main thing to consider is that brewers yeast leaves behind plenty of sugar in beer that [wild] Brett is capable of eating. This gives wild Brett a huge advantage such that it is simply impossible for Sacc to stop Brett from growing in beer. Obviously wine is completely different in this regard -- Sacc growing faster is all the advantage it needs in wine and vintners use standard practices to minimize Brett character like sulfites and repeated racking.
Same goes for wild LAB which is not present at all in fresh wort post-boil, but once introduced it can *very* easily compete against yeast both short-term (Lacto in unhopped wort) and long-term (Pedio in hopped wort), adding lots of lactic acid, drastically changing the beer. OTOH fruit must has low enough pH combined with minimal buffering capacity that LAB growth isn't enough to contribute significant character. The tartaric and/or malic acid already in the must are stronger-tasting than lactic acid so any lactic is non-significant.

Correct me if I'm wrong about any of this.

 

[MizzouFermentationScience]

There are things to consider when taking experience from winemaking and trying to apply it to brewing.

Wort is for practical purposes fully yeast-free before we think about pitching yeast. This gives wild yeast (collected away from the brewing environment) a clean slate to reproduce.
I'm guessing you don't sterilize your must before transferring it into sterile tanks. I recently read that fresh-pressed apple juice has around 100 Billion yeast cells per mL. These wild yeast cells have spent many many generations living on this fruit and having to fight for survival against the environment and other microbes, so it's really no surprise they can start fermentation so quickly. I'd think the press is basically impossible to fully sanitize so you'd also get hardy house strains growing there and inoculating everything you press.

The other main thing to consider is that brewers yeast leaves behind plenty of sugar in beer that [wild] Brett is capable of eating. This gives wild Brett a huge advantage such that it is simply impossible for Sacc to stop Brett from growing in beer. Obviously wine is completely different in this regard -- Sacc growing faster is all the advantage it needs in wine and vintners use standard practices to minimize Brett character like sulfites and repeated racking.
Same goes for wild LAB which is not present at all in fresh wort post-boil, but once introduced it can *very* easily compete against yeast both short-term (Lacto in unhopped wort) and long-term (Pedio in hopped wort), adding lots of lactic acid, drastically changing the beer. OTOH fruit must has low enough pH combined with minimal buffering capacity that LAB growth isn't enough to contribute significant character. The tartaric and/or malic acid already in the must are stronger-tasting than lactic acid so any lactic is non-significant.

Correct me if I'm wrong about any of this.

I think you misunderstood my thoughts. I’m saying that even dirty grapes full of wild yeast get fermented by dominant commercial strains found in the winery environment. I think the chance of finding a truly native yeast capable of surviving 4% ABV is very low- and in a homebrewers house I suspect that there are commercial strain present. Strains that have been selected not only for their beer brewing ability, but also for their ability to “infect” and dominate breweries (e.g. there is a reason the native yeasts that begat commercial strains were the ones dominating their respective breweries).

As for Brett, there is absolutely the possibility of Brett being in a “native” culture, but the fermentation kinetics and aromas should be a pretty sure identifier.

As for where you are wrong (because you asked, not because I’m an a-hole), there are plenty of residual sugars in wine for Brett to feed on, especially from the roasting of wood barrels. But without an inoculation, it takes a few months at at minimum before Brett character is noticeable. Brett is one tough SOB and no reasonable amount of sulfites or normal pH range will stop it. Alcohol can inhibit it above 14.5%, but unfiltered wines need to find microbial balance to prevent Brett from taking hold. Typically, I worry most about nitrogen sources in regard to Brett.

As for LABs, they are a huge concern for wine. My biggest concern with spontaneous fermentation is LAB and I scope daily to check for it. We will eventually use oenococcus to convert malic acid into lactic acid but if this is done in tank in the presence of oxygen, it can ruin wine with off flavors. My cure for LAB infection? Pitch a commercial strain and it will put LAB out of business.

Long term contamination is very different than primary fermentation; when microbes aren’t fighting for scraps a dominant strain almost always emerges. I’m wary that a home brewer without an autoclave is going to isolate the 1 in a million wild yeast that can ferment wort dry, call me a pessimist. I still believe in the funk, I love the unpredictability, I just think it’s silly to isolate a clean strain and make clean beer with it- we have clean yeast, give me that funky stuff.

 

[FunkedOut]

Appreciate your insight here and explaining this.

My comment of not believing in wild yeast refers to my belief that commercial strains are so strong and probably ubiquitous in a homebrewer’s house that my bet is that you probably caught a few cells of it and it out competed any wild yeast that may have been in the wort.

I always store commercial yeasts in small jars in the fridge inside my house.
I always make starters inside my house.

I always brew in the garage, at the outside door’s edge, with the overhead door wide open.

Once I’ve transferred the wort to a from the kettle to a keg, I bring out the decanted starter and add it to the keg.

Then the keg goes to a shed for fermentation.


It’d be pretty disappointing to go through this effort, and drop $20 on Petri dishes to catch something I already had.
I hope you believe in something that doesnt apply here.

The day I filled those jugs, both brews were inoculated with W-34/70.
When this isolated culture is grown up a bit, i should make a small batch of pilsner and pitch half of it with it, and the other half with W-34/70.

 

[FunkedOut]

On the bright side, if this is just a commercial yeast infection, it seems like rushing to pitch yeast is not as big a deal as it’s made out to be.

New craigslist ad going up, bring your wort to my garage for free commercial yeast - $5.

 

[FunkedOut]

A couple days in and the only difference I could observe is that both vials are a bit cloudy when shaken.
It’s not possible to capture well in a picture.

I figured since both vials did same, I’d go ahead and trash the 3 colony vial and continue to propagate the single colony vial.

Next step up is a 50mL starter with 1.020 wort.
Pilsen light DME and distilled water. Same process as the initial 5mL starter.

(yes, this is a tiny 100mL jar)

 

[FunkedOut]

nothing exciting.
stepped up starters a couple times.

pint jar:

2L flask:

looks like, smells like, acts like yeast.

 

[bassist286]

Keep it going man! This is interesting stuff.

 

[FunkedOut]

So I got the yeast put away in a little jar along side all my other yeasts.

I was planning on brewing a bit of a larger batch on my next brew so I could fill two half gallon jars with wort and pitch one with this stuff and one with W-34/70 to see if they were any different.
The comparison effort was an idea driven from the turd in the punch bowl left by @MizzouFermentationScience.


On a very related note, this past weekend, I had a brew day where once again, I brewed two beers; a mexican lager with WLP940 and an amber lager with W-34/70. I took what was left in the kettle for each brew and dumped into a water jug again. Each batch in its own jug. Lids tight. Planning on tossing later.

>>> Fast Forward to last night >>>

I was in the garage working on some things and saw the jugs had swollen like balloons, krausen and all. I loosened the lid, a burst of CO2 came out and bubbles started coming out of solution. That lasted a good bit. I have to conclude that the yeast that was in there did not make it past the lid, as it was tight enough to hold pressure.

Also, when I pitch the yeast, it is from a starter that is built inside the house, and doesn't make its appearance until the wort is in the fermenter.
I simply pour the decanted starter into the keg, seal it up and carry it away about 100' to the fermentation chamber.
The kettle has its lid on during this process.
The kettle gets its lid on as soon as the immersion chiller comes out.
Flame out to lid on only takes about 20 minutes.
That has to be the window where the infection/inoculation happens.
The kettle is at the edge of the garage, fully open, wind blowing during this time.
5 min whirlpool with pump, followed by 30 min rest, then the transfer to fermenter via the valve.

Still could be commercial yeast that jumped from the starter a month ago and hung around in the air to fall in the kettle.
Or could be wild yeast that jumped from the oak trees all around and rode the wind into my kettle.
Not sure which is more likely or which happened.

 

[FunkedOut]

Time for this thread to get a bump.
I have the isolated, propagated yeast sitting in the fridge, along side the suspect 34/70.

I am planning a couple brews that are a couple weeks out; a Biere de Garde and a Blonde Ale.
The plan was to brew an extra gallon or so and fill to half-gallon jars with the extra wort.
Then pitch one with the wild caught and one with 34/70. Take pictures along the way and see any differences between the two.
Then a few week bottle condition and the blind taste triangle.

Fermentation temps will be 63*F, as both those panned brews will use a kolsch yeast that does well for me at that temp (2575-PC).

Here's the question:
Which brew should I extend for use as the test wort?
Biere de Garde?
Blonde Ale?

BDG is higher gravity and will give the yeasts a work out.
Blonde is lighter in flavor with a touch of wheat to highlight the yeast.
What say yous?

 

[RPh_Guy]

Blonde?!

 

[kh54s10]

My less than scientific approach was to make a weak starter, drop in a hibiscus flower and see what happens. The starter fermented so I stepped it up. When it seemed I had enough yeast I made a SMaSH with Rahr 2 row and Centennial since I have used it often and have an idea of what it should taste like.

Fermentation of the SMaSH proceeded normally and went from an OG of 1.052 to an FG of 1.013. At bottling I tasted it and it did not taste like any yeast that I have used??

Based on the previous replies I probably have a commercial strain since I did the starter in the area where I usually do my starters and also a mere feet from where I ferment my beers. But who knows?

The bottles have been conditioning for about 2 weeks now so I will be chilling one to try soon. I will post my observations then.

 

[FunkedOut]

My plan to prove or disprove the commercial strain hypothesis is to pitch the two strains side by side and see if they differ. If they do differ, I am headed to the database hall of fame at bootlegbiology.com!

Blonde?!

Thanks?!

I like that punctuation. I will use it to reply to a text in the near future:
"I love you too?!"

 

[FunkedOut]

The time is drawing near.
I've got that 1.053 blonde planned for this coming weekend, so I decided to make a starter for the wild? yeast and the suspect source, W-34/70.
Here is the pair of them as stored in my fridge:

Made a 1.020 starter with pils DME and split it into two mason jars for the shaken, not stirred method, since my stir plate is busy with the kolsch yeast for the blonde.
These will ferment at room temp; 72*F.
Here are the jars after pitching the yeasts:

Plan is to save 100 billion cells from each starter for future use again.
That leaves 20 billion cells (5oz of beer) in each 1/2 gallon jar.
I am going to leave all the starter wort in the jar, then add 1/4 gallon of the blonde to each jar, place an airlock on it and place in the fermentation chamber at 65*F.
I figure the warmer-fermented starter wort might offer a chance for any yeast character to come through better.

I'll be taking pics of the starters and the beers each day to note any visual differences.

 

[FunkedOut]

Noticed the first difference this morning, approximately 10 hours after pitching.
The yeast and the starter wort were both a 37*F, so I just pitched cold, shook it and set it on the counter.
This morning, I decided I would shake them again to make sure they get some good aeration.

Shook the W-34/70 for a couple minutes, set it down and loosened the top. A decent venting came out, almost like opening a soda bottle.
Shook the wild? for about 2 seconds because the foam was crazy and blew past the tightened lid for a few seconds after I stopped.
I'd say the wild? was more active and made more CO2 overnight than the W-34/70.

notice the yeast/trub at the bottom of the wild? jar that didn't get mixed in because of the interruption in the shaking:

 

[FunkedOut]

So this morning, about 34 hours after pitching, I removed the lids to smell each starter.
The W-34/70 smelled like green beer, a bit of sulfur.
The wild? yeast smelled like green beer, but a good bit cheesy.

The wild? yeast seems to be a bit more flocculent than the W-34/70:

I decided to shake them up (off gassing them first), enough to get everything in suspension.
These next few pics are maybe 30 seconds apart from each other:

 

[FunkedOut]

48 hour mark and no more activity for either yeast.
I swirled each one up so I could pour off enough of each to store 100 billion cells for future use, and left about 20 billion cells (lager pitch rate) for the 1/2 gallon of blonde wort coming this weekend.
Again I smelled sulfur coming off of the W-34/70 and nothing but clean beer smell from the wild? yeast.

All 4 jars are in the fridge now until the weekend, maybe Friday is a brew day.

 

[RPh_Guy]

If it ends up cheesy I vote for adding some dill, oregano, or basil.

 

[Calaeb]

Have really enjoyed following this thread, can't wait to see the results from the brew day!

 

[divrack]

Mainly posting to stay subbed, but have been planning an intentional side hobby of yeast foraging around the local woods and Glens. I have a culture of a wild Brett infection that has made some of my favorite beers that stemmed from a random infection of a wit. It's distinct from any Brett I've tasted but closest to c. Has a kind of honeycomb flavor.
Science and beer rock

 

[FunkedOut]

I brewed up that blonde ale on Friday. Came out 1.053 as planned.
Grabbed a quart for each jar before racking to the fermentor.
Here's a pic right after pitching (64*F):

Right after pitching, they went into the fermentation chamber that is set to keep the blonde wort (thermowell) at 65*F.
Here's day 1 (19 hours after pitching):

Here's day 2 (38 hours after pitching):

 

[FunkedOut]

Here's a pic from day 4:

Day 5:

 

[FunkedOut]

This is day 9:

I really have not found any visually observable differences between the two batches outside of the airlock.
Both airlocks contain starsan from the same bottle, poured back to back.
For some reason, the W-34/70 has bubbles in every picture.
Maybe the wild? yeast finished sooner?
Maybe the wild? yeast doesn't put out as much CO2?
Maybe nothing.

(there are silicone seals between the jar and lid, as well as lid and airlock)

 

[FunkedOut]

So I've been away for a week and just got back.
The jars stayed in the fermentation chamber at a steady 65*F from day 1.
After 10 days of fermentation, ambient temps in the fermentation chamber rose 1*F each day, reaching 70*F on the last day.
Here they are after a cold crash to 32*F:

I transferred them to "bottling buckets" where I mixed each jar with 10 grams of DME; should make 2.6 volumes.
(I'm new to bottling, and last time I used cane sugar, ended up with an apple cider taste in base malt SMaSH's)

I got a bomber and a bottle out of each jar. I used a clear bottle to keep an eye on things as they progress.

 

[FunkedOut]

Observations:
When I opened up the fermentation jars, the W-34/70 smelled of sulfur while the wild? smelled of banana.

Tasting what was left of each bottling jar, the W-34/70 tasted like green apple while the wild? tasted kinda fruity.

Unfortunately, I didn't have enough left over to measure FG. I'd rather have an extra bottle of each to hold onto longer. I figure I can always measure the gravity in a few weeks from each bottle.

I'll reserve my final judgement until then, but I have to say that based on what I've seen, smelled and tasted so far, I think these are definitely different yeasts. I'll have to get a blind triangle test to remove my bias.

 

[timcook]

About 10 days ago I made a DME starter at night. Before it cooled, I covered the starter with my BIAB bag & placed it under an apple tree in my backyard. In the morning, I brought the starter indoors. Within hours there was signs of activity. Below is a picture. I have unsealed the lid once or twice to relieve some of the pressure. To me, it smells of apples (certainly not pleasant.) To be honest, I am a little hesitant to taste it. Should I build the starter up with another pint before tasting It? Should i let it ride longer? I'm in no hurry. On the bottom of the jar, it looks like grey colored trub.

Tim

 

[RPh_Guy]

@timcook
I'd let it ride for 2-3 weeks. Many contaminants will die during that time.
At that point if it smells ok, taste it.
If you like it, step it up or pitch into a batch if you feel adventurous. The flavor should be a little more clean since some/most/all of the bacterial organisms were killed, especially if you use hops.

Happy wrangling!

 

[FunkedOut]

Today marks 3 weeks after bottling.
I left the bombers at room temp and placed these two clear bottles in the fridge to get nice and cold for at least a week before I pop them.

Just a tad bit more dregs in the wild? vs the W-34/70.

 

[jfolks]

Today marks 3 weeks after bottling.
I left the bombers at room temp and placed these two clear bottles in the fridge to get nice and cold for at least a week before I pop them.
View attachment 577338

Just a tad bit more dregs in the wild? vs the W-34/70.

Excited to hear the results!

 

[FunkedOut]

 

[RPh_Guy]

And the long anticipate result?

 

[FunkedOut]

Couldn’t wait.
I tapped the Blonde Ale last night and found that it tasted really bitter and was cloudy (not bright).
The Kölsch yeast must still be in suspension, as I was storing the keg at room temp.
I figured popping these bottles would help me determine if the wort sucks or it was the yeast.

 

[FunkedOut]

Both of these are clearer and better tasting than the keg, so here’s to hoping that a few weeks in the cold will save the keg.
On to these two...

Different for sure.
The wild? yeast gave wifey goosebumps, while she instantly said that the 34/70 was way better than the keg.

I find that on the nose, the 34/70 shows it’s lager personality; most noticeably the sulfur.
The wild? smells fruitier. There was a peach flavor in the wort prior to fermentation that is gone from the Kölsch and 34/70 but is still there on the wild? beer.

The flavor on the wild? has some sour and hoochie qualities.
The 34/70 is all lager. Smooth as silk and much maltier than the wild? version that lets the hops (Mandarina Bavaria & Mosaic) come through more.

I have no doubt these two yeasts are different.
I will be contacting the bootleg biology crew with this capture.
Not sure I know what brew to brew with this yeast yet. But it does not make a bad beer.
Maybe I’ll try some dark wort next...

 

[divrack]

thank God, the suspense was too much for me. youre way more patient than I am.
they call me Mr wine thief..

 

[FunkedOut]

No kidding. This process seemed to take forever. It has been 4 months since that first brew day.
Just have to keep your mind occupied with other things. That is something I am never short of; things to do.

I have to remember to take gravity samples of the bombers and get a triangle test in.
I figure another few weeks at room temp followed by several weeks cold before I pop those bottles.

 

[Miraculix]

No kidding. This process seemed to take forever. It has been 4 months since that first brew day.
Just have to keep your mind occupied with other things. That is something I am never short of; things to do.

I have to remember to take gravity samples of the bombers and get a triangle test in.
I figure another few weeks at room temp followed by several weeks cold before I pop those bottles.

And I am the lucky one, finding this thread only just after the bottle has been opened

 

[timcook]

Update: I let my wild fermentation with a starter wort go a few more weeks as recommended. I was pleasantly surprised by the "clean" taste. My plan is to step up the starter next week then eventually blend it with a fermented beer.

 

[RPh_Guy]

Update: I let my wild fermentation with a starter wort go a few more weeks as recommended. I was pleasantly surprised by the "clean" taste. My plan is to step up the starter next week then eventually blend it with a fermented beer.

I would try it as a primary. Although unpredictable, it's most likely you have Saccharomyces with some lactic acid bacteria, so adding it to a fermented beer might not have much effect.

No harm in your plan though if that's what you want to try. Be especially careful about protecting from oxygen.

Cheers

 

[kh54s10]

My less than scientific approach was to make a weak starter, drop in a hibiscus flower and see what happens. The starter fermented so I stepped it up. When it seemed I had enough yeast I made a SMaSH with Rahr 2 row and Centennial since I have used it often and have an idea of what it should taste like.

Fermentation of the SMaSH proceeded normally and went from an OG of 1.052 to an FG of 1.013. At bottling I tasted it and it did not taste like any yeast that I have used??

Based on the previous replies I probably have a commercial strain since I did the starter in the area where I usually do my starters and also a mere feet from where I ferment my beers. But who knows?

The bottles have been conditioning for about 2 weeks now so I will be chilling one to try soon. I will post my observations then.

My update. The beer ended up a bit on the thin side. The taste was different than other yeasts that I have used. I am no good at describing flavors, but it was clean and crisp. I liked it quite a bit. I haven't tried it again, but have some slurry in the fridge. I think it is time to do a starter and use it again. But, since it has been a while I don't think I would be able to determine any difference.