# Wild Yeast Fermentation



## Deebo (1/11/11)

So I was a bit bored and collected a bunch of wort and trub in a 2l soft drink bottle and thought I'd sit it outside to see if something would ferment it.
Today it has a nice froth on the top and actually smells pretty good.. is there anything I should know about before taking a swig in a few days to see how it tastes.
It was 31c here today so I am suprised it doesnt have an awful smell to it really (it is sitting in a shady spot).


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## ekul (1/11/11)

You should know about skunking. The UV light can make your hops turn into skunk goodness. BUt you'll smell it before you'll taste it anyway. Maybe put the bottle in a dark place now that its innoculated.


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## Deebo (1/11/11)

ekul said:


> You should know about skunking. The UV light can make your hops turn into skunk goodness. BUt you'll smell it before you'll taste it anyway. Maybe put the bottle in a dark place now that its innoculated.



Thanks for the tip, have just stuck it in a dark room.


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## CONNOR BREWARE (2/11/11)

Deebo said:


> Thanks for the tip, have just stuck it in a dark room.




was there anything in particular near like fruit trees,keep us updated


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## Deebo (2/11/11)

Duke of Paddy said:


> was there anything in particular near like fruit trees,keep us updated



Nah no fruit close to where I put it.. I was actually a bit suprised that stuff got down the small neck of the soft drink bottle in such a short time. 

Heres a pic, stirred up the trub a bit moving it into the light.


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## pk.sax (2/11/11)

+1 very interested. Been trying wild with cider of juice, be great to know what it does to beer.

Maybe you can blend half pints of wild beer with normal and tell us if that's any good too?!


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## Swinging Beef (2/11/11)

You are a brave man.
All my experiments with natural airborn yeasts in Australia have proved to be quite revolting.
We do not live in Lombeek.


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## mckenry (2/11/11)

Deebo said:


> is there anything I should know about before taking a swig in a few days to see how it tastes.



Probably that youre going to need somewhere to spit it out really quickly. :lol: 

Interested to hear about it though. I've never had a 'natural yeast' / spontaneous fermentation taste good.


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## Deebo (3/11/11)

mckenry said:


> Probably that youre going to need somewhere to spit it out really quickly. :lol:
> 
> Interested to hear about it though. I've never had a 'natural yeast' / spontaneous fermentation taste good.



I wasnt expecting more than a pile of mould really, but had another sniff today and it smells like beer fermenting normally smells to me. 
It has got a lot more murky now that the fermentation is moving the trub I had in there all around. (it is kinda of mesmerising watching it move around, will upload a video if I can remember)
I do have another smaller bottle of wort in the fridge without any trub I may try to innoculate with the yeast from this one if it doesnt turn into a horrible sour mouldy mess.


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## CONNOR BREWARE (3/11/11)

Loving this thread

If you knew this was not gonna be rank that size bottle could make a good starter for the experiment on a bigger scale. Still you'd have to be a braver man than to risk that much wort.


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## esssee (3/11/11)

Check out the October 20, 2011 episode of Basic Brewing Radio link. They spoke about Spontaneous Fermentation. Interesting Stuff.


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## super_simian (3/11/11)

I've had spontaneous fermentation occur (due to a brain fart) to a small batch of wort ~500ml. The smell wasn't particularly off, so I let it go (in another part of the house from my brewing gear - I'm a suspicious man!) After 2 weeks I had a bit of a look/smell/taste. It had thrown a kind of slimy 'krausen', smelled very 'phenolic' and hadn't attenuated much. The taste was mainly sweetness, with a bit of a baked-bean aftertaste. Not awful, but not great.


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## drsmurto (3/11/11)

Not necesarily bad. A lot of wine is made using wild yeast.

Wild ferments normarily result in large ester formation.

If i was doing this i would be treating it like normal beer so fit an airlock or somehting to protect it from any further 'contamination'. You could always add some SO2 to inhibit baterial growth (lacto/aceto) at 30mg/L using potassium metabisulphite. It wont stop the yeast from fermenting at that level.

You are likely to see the gravity end up much lower than with beer yeast so you might be best to either stop fermentation (rack/crash chill) at your desired FG to retain some body.

Another person interested in seeing how this pans out. :icon_cheers: 

I have mates who make wine naturally at a professional level who are interested in doing the same with beer.


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## Josh (3/11/11)

I've done it a couple of times. Pretty pleased with the results. Though after 7 months, the Framboise is pretty subdued if you were looking for overly funky flavours. But it finished at 1.003 from 1.036 I think. Makes a very tasty, ridiculously sessionable beer. At least that's the experience I have in my backyard. Everyone will be different.


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## Deebo (3/11/11)

Looks like fermentation has stopped today (has been pretty warm in perth the last few days so may effect the flavour somewhat). 
I will take a sg reading and have a taste on the weekend and if it isnt horrible will maybe try collecting some of the yeast and fermenting something else in a cooler spot.
I have a porter waiting to go in a cube so I could draw some of that off for the wild yeast and ferment the rest as normal, or just try another small sample using about 750ml of wort I have in the fridge (I think a lighter beer would give a better idea what flavours the yeast are putting out). 



Edit: Couldnt resist so had a small swig.. It tastes slightly sweet (probably a bit under attenuated) and has a very slight bitter taste but overall is pretty drinkable. I reckon once chilled and carbed could pass for an ok beer. Considering it had temperature going against it I am already thinking I may risk an old fermenter and a batch of beer to give it a shot when I get a chance.

In the mean time is the best way to store it just chuck it in the fridge? I think I will try drawing off 750ml into a PET bottle and using a carbonator cap to give it some fizz after I do the SG reading.


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## drsmurto (4/11/11)

Whats the SG?

If it has finished fermenting then i would be crash chilling it for a few days to drop out as much yeast as possible and then pour into another bottle and use the carbonator cap.

Sounds like you are onto something.

I like the idea of a wild ferment but not something funky.


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## argon (4/11/11)

I'm really keen to try this too. Like the idea of a few wild ferments from trying to select the most preferable strain. 

Something like set-out half a dozen bottles around the place. Let them inoculate/ferment out and select the best tasting one. Then use that to inoculate the next small batch in a controlled environment. Over time (probably a long time) be able to select the house strain.

Also one thing to consider... the bottle may have been inoculated by a strain of yeast you've been using to brew with in the past and it's somehow got into the bottle. So it may not be a wild yeast at all. Not that it makes the experiment any less fun though. :icon_cheers:


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## hsb (4/11/11)

I was reading Wheeler/Protz on Lambics/Sours/spontaneous fermentation last night (as you do)

Interesting stuff to a complete noob at wild fermentation like myself. They pointed out some stuff that is probably obvious to others but wasn't to me. Essentially pointing out that, unless you live next door to an orchard or a cereal crop, there's probably nothing unique about your local environment, the wild yeasts/microorganisms are just everywhere, if not already in your wort - it's about setting the right conditions to encourage growth from the ones you want (and suppressing the ones you don't.)

I can scan it if anyone's interested, though like I say probably common knowledge to many of you - and the focus was more on lambics/sours etc..


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## Greg.L (4/11/11)

A wild ferment is unlikely to be a single strain of yeast. Part of the flavour is from a progression of different yeast strains. If you save the yeast residue from your ferment it will probably taste different next time. The point with wild ferments is you have to start from scratch each time.


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## Deebo (4/11/11)

Haven't done a SG reading yet hopefully will do one tommorow then chill it down.

The fact it wasnt weird/sour etc made me think it may be a brewing yeast but I have only ever pitched yeast inside (the bottle was left outside). 
I do ferment in a fridge out there, but the yeast would have to get out of the airlock and out the fridge door and traveled about 3 meters then into the bottle. 

Only other way I can think that brewing yeast got in is that I do pour my trub down the drain.. but it would have to have hung around the drain for about 2 weesk then got out up into the air and into the bottle.
I also usualy pour starsan and napisan down the drain after it so not sure how well it would survive in there.


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## drsmurto (4/11/11)

Deebo said:


> Haven't done a SG reading yet hopefully will do one tommorow then chill it down.
> 
> The fact it wasnt weird/sour etc made me think it may be a brewing yeast but I have only ever pitched yeast inside (the bottle was left outside).
> I do ferment in a fridge out there, but the yeast would have to get out of the airlock and out the fridge door and traveled about 3 meters then into the bottle.
> ...



It's a myth that all wild yeast are sour.

Natural/wild ferments are quite common in winemaking and the end result is not weird or sour.


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## jyo (4/11/11)

Watching with interest! :icon_cheers:


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## [email protected] (4/11/11)

Im following this one with interest as well. 
I guess its coming into the best time of year to try this out myself.

We have a small orchard about ten trees, apples, pears, some plums oh yeah there's a walnut tree in there somewhere to.
Old mate 2 doors down grows a decent about of grapes for his own wine making.

I put slurry down the drain ONCE. All our grey water goes to a designated area near orchard.
The inside of the house stank for days, the smell of the yeast eating what ever else goes into the drain.


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## Deebo (5/11/11)

Relaxing fermentation footage.. ignore the woman giving birth in the background.. wife was watching something on tv


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## Deebo (5/11/11)

Final gravity was 1010. Decided to just prime with sugar as I dont know if I want the wild yeast near my keg lines etc.
Didn't taste as sweet as I though it was yesterday and noticed a slight sulphur smell that you get with lager yeast sometimes.

Poured most of the beer out and topped up with water to maybe try and seperate the yeast and trub a bit. Now I just need another 2l bottle to pour into.


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## raven19 (5/11/11)

Interesting thread thus far. Yeasts of old were all repitched from previous batches, as such originated from 'wild' ferments, just 'controlled' to a mild degree based on selection from brewers at the time.

Keen to hear on the flavours in the resulting beer.


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## raven19 (5/11/11)

DrSmurto said:


> It's a myth that all wild yeast are sour.



Yeah but sour ones are so tasty!!!


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## Deebo (7/11/11)

Son of wild yeast:





Decided to rinse the yeast and add it to some clear wort I had in a bottle in the fridge to see what effect no trub and better temp control will give.


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## CONNOR BREWARE (14/11/11)

Deebo said:


> Son of wild yeast:
> View attachment 49892
> 
> View attachment 49893
> ...


When will you be opening wild yeast MK I for the taste test? Will be interesting to hea the outcome.


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## Nick JD (14/11/11)

I wouldn't be surprised if your house (and especially the area where you dump trub etc) is "infected" with beer yeast.


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## Deebo (14/11/11)

Nick JD said:


> I wouldn't be surprised if your house (and especially the area where you dump trub etc) is "infected" with beer yeast.



Would be interesting to find out. 
How long can yeast survive and under what kind of conditions?
I suppose the drain would be pretty cool but I do pour starsan and nappsan down there after cleaning etc.


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## Nick JD (14/11/11)

Deebo said:


> How long can yeast survive and under what kind of conditions?




Dunno. Considering we are adding 100 billion to a batch ... and _then _they start multiplying, I reckon our houses are all well-infected with beer yeast - more so if we have sediment in the bottom of bottles and glasses and in your breath and our clothes and in the carpet and in the shed etc etc.


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## stux (14/11/11)

How long does dried yeast last 

It only takes one!


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## Josh (14/11/11)

I pitched my latest spontaneous ferment 2 months ago. Only in the last few days, I have noticed vigorous fermentation in the carboy. I'm guessing they took a while in the growth phase?


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## Lecterfan (11/1/12)

The background: I took about 5L of left-over APA and left it uncovered for about 36 hours (I say this like I meant to, but it was a simple byproduct of drunken laziness). I then poured it into a bucket that I had cleaned with hot water and then starsanned, covered haphazardly in glad wrap and forgot about it. It took a while but for about 2 or 3 weeks now it has been covered in a luscious thick krausen and the smell is so sweet it is fantastic. However, a few days ago a stinking little mongrel no good vinegar fly made its way in while I was messing around in the vicinity of the bucket (the covering was loose as I was not taking this at all seriously) and appears to be dead but on top of the krausen. 

The question: should I attempt to fish it out or just trust that the wild bacteria/yeast that is in there already will prevent the vinegar fly carcass from ruining what is shaping up to be a seriously interesting (and surprisingly sweet smelling) experiment? Thoughts?

I was hoping that if this beer turned out interesting in a tasty way I would also culture the yeast to try on other things.


edit: and I am aware this seems a ridiculous question, but I have posted it simply as I have no experience with 'wild' ferments or even with bugs on top of krausen...my gut is telling me to starsan a spoon and whip it and the surrounding krausen out...


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## [email protected] (11/1/12)

Lecterfan said:


> The background: I took about 5L of left-over APA and left it uncovered for about 36 hours (I say this like I meant to, but it was a simple byproduct of drunken laziness). I then poured it into a bucket that I had cleaned with hot water and then starsanned, covered haphazardly in glad wrap and forgot about it. It took a while but for about 2 or 3 weeks now it has been covered in a luscious thick krausen and the smell is so sweet it is fantastic. However, a few days ago a stinking little mongrel no good vinegar fly made its way in while I was messing around in the vicinity of the bucket (the covering was loose as I was not taking this at all seriously) and appears to be dead but on top of the krausen.
> 
> The question: should I attempt to fish it out or just trust that the wild bacteria/yeast that is in there already will prevent the vinegar fly carcass from ruining what is shaping up to be a seriously interesting (and surprisingly sweet smelling) experiment? Thoughts?
> 
> ...



Yeah go with your gut, fish it out! If there is a decent krausen it should be protecting the wort from the fly carcass.
Sounds interesting, id let it ferment out, take readings ect, bottle it up (PET) and see how she goes.
This is something i have been meaning to do on purpose but have not got around to it.
Let us know how it goes


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## ShredMaster (11/1/12)

Lecterfan, I guess the answer would depend on whether you actually intended to drink the final product and how much private scientific research you can do with a bucket of left-over wort, some wild yeast of some type and the chance of some vinegar.... Would you, actually, drink it?


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## Deebo (11/1/12)

Had forgot about my wild yeast ferment. How long is recommended for wild fermentations to age before trying them?
From what ive heard a year would probably be good to give whatever bacteria is in there a chance to do their thing?


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## Lecterfan (11/1/12)

I always intended to bottle it once completed and then sample it. If it's any good then hell yes I'll drink it...and let's not make the vast leap from the word 'experiment' to the phrase 'scientific research' just yet :lol: .

Cheers B4u, job done - you never know, it might be the protoype for my next case swap beer and you can sample it...

I'll certainly report back after sampling.


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## Deebo (23/3/12)

Drank the original wild yeast this arvo (the one that fermented in 30c heat for a day or two), was suprisingly not bad (pitty I cant remember what recipe the wort was from) tasted to me like an average english ale.
It was cloudy and none of the yeast had really settled in the bottle which seemed strange (unless wife gave it a shake when I wasnt looking). Also had very little carbonation/head retention.



Still have the second batch that was done under better fermenting conditions in the cellar.

I have some more spare wort I extracted from the trub of todays brew so might try another one.


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## Bizier (24/3/12)

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.


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## Mr. No-Tip (3/2/13)

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.


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## bingggo (26/4/14)

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?


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## mje1980 (26/4/14)

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.


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## manticle (26/4/14)

bingggo said:


> 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.


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## bingggo (29/4/14)

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


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## manticle (29/4/14)

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)


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