Really low attenuation

[OldDogBrewing]

Last week I made an spontaneous ferm beer, after around 5 days fermenting quite violently (it blew off 3 times) I just checked the actual gravity and it just attenuated 15% of the sugars present in the wort

I mashed at 70°C and added a spoon of flour to the boil to avoid a turbid mash, the wort is pretty unfermentable, but is it that unfermentable or I have something else in my wort that isn't yeast that caused the vigorous reaction?

I basically have a week old wort with only 1% ABV so I'm quite worried about what can be living in there, as there is no alcohol to kill it, the yeast should have had outgrown anything by now but anything that was there before is probably alive as there is nearly no alcohol to kill it, it smells like fermentation, just a bit like fish fermented sauce

Should I keep the wort and see what happens in maybe a couple weeks to a months? Or is it too dangerous and its a dumper?

 

[RPh_Guy]

A spontaneous beer is a project lasting months to years. A week is too soon to do anything, unless there's mold.

It's normal for wild yeast to only have a low attenuation, although it's usually higher than 15% AA. You may want to consider adding a Brettanomyces culture +/- bacteria.

Did you add hops?

 

[OldDogBrewing]

A spontaneous beer is a project lasting months to years. A week is too soon to do anything, unless there's mold.

It's normal for wild yeast to only have a low attenuation, although it's usually higher than 15% AA. You may want to consider adding a Brettanomyces culture +/- bacteria.

Did you add hops?

I added 12 IBUs using a low AA East Kent Goldings bag I have at home, they don't reach 5% AA

I know is a long term project and the wort is unfermentable, but I was expecting a 30 to 40% attenuation by now and around 2 to 3 ABV to make the wort unsuitable for life to certain bacteria, now I don't know if I should leave it for that long as anything can grow in there with this conditions

I can pitch some Kveik and see if it cleans any fermentable sugar and bumps up the ABV to a sake ageing ABV, should I try that?

 

[RPh_Guy]

I can pitch some Kveik and see if it cleans any fermentable sugar and bumps up the ABV to a sake ageing ABV, should I try that?

Not a bad idea. Of course that removes the novelty of it being "spontaneous".

 

[OldDogBrewing]

Not a bad idea. Of course that removes the novelty of it being "spontaneous".

I know that, that's why I don't want to do it but I think it may be dangerous to hold this wort like that, the hops probably have inhibited some stuff but definitely there's something in there that isn't yeast, as yeast with such vigorous reaction would have attenuated at least a 30%, unless is a strain like London that is unable to break chains that other strains can and the 70°C mash ks to difficult for it, but it's dangerous anyway, maybe I will wait a week or so and see if it kept eating a bit more

If I see it's around 3% ABV or so I will keep it, if not, I will have to decide if I pitch Kveik to an infected wort with God knows what or if I just dump it and wait until the temperatures are good again which is probably a couple months wait

 

[RPh_Guy]

yeast with such vigorous reaction would have attenuated at least a 30%,

?? Your calculations show otherwise. CO2 production and gravity drop would be pretty much entirely from the yeast. The excessive blow-off just illustrates the difference between wild yeast and the commercial yeast krausen you are used to seeing.

All "spontaneous" fermentations have both yeast and bacteria. It's not really anything to be concerned about in the long run. Mold could definitely be a problem, but you would see it.

If you decide to add kveik or other commercial Saccharomyces, I would suggest adding some yeast nutrient as well.

 

[OldDogBrewing]

?? Your calculations show otherwise. CO2 production and gravity drop would be pretty much entirely from the yeast. The excessive blow-off just illustrates the difference between wild yeast and the commercial yeast krausen you are used to seeing.

All "spontaneous" fermentations have both yeast and bacteria. It's not really anything to be concerned about in the long run. Mold could definitely be a problem, but you would see it.

If you decide to add kveik or other commercial Saccharomyces, I would suggest adding some yeast nutrient as well.

I was worried about all the enterobacterias that are killed ones the yeast bumps up the ABV, I know anything else is inhibited by hops or can't grow in beer, except mold but there are no signs of it

Don't heterofermenting Lactobacillus strains produce CO2 and ethanol? I didn't checked the Ph but I will do so the next time I sample it

 

[Kickass]

Why do you keep referencing your wort as unfermentable? Is it the higher mash temp or grains you used?
Just a thought but unfermentable wort and spontaneous fermentation sound like a very long, slow road with a high potential for a poor outcome.

 

[OldDogBrewing]

Why do you keep referencing your wort as unfermentable? Is it the higher mash temp or grains you used?
Just a thought but unfermentable wort and spontaneous fermentation sound like a very long, slow road with a high potential for a poor outcome.

Because I mashed at 70°C and added a tablespoon of raw flour to the boil, to simulate a turbid mash, it just needed to be this way if a wanted to have the biggest influence from the bacteria, that way everyone has food for them in the wort

So obviously it's not a highly fermentable wort but there should be enough sugars for at least achieve a 50% attenuation by the yeast, it's not the first time I mash that high and never ever have I had that low attenuation in a week, I will wait anyways until next week prior to taking a decision

 

[Kickass]

Ok, I was curious if there were other factors contributing to your “unfermentable” wort. 70 is high but not outrageously high, and depending on how you got there, you may have allowed some beta amylase conversion to take place.

As far as the flour in the boil, I’m open scrutiny on this, but I’m not sure that would make your wort any more unfermentable.

In total, it sounds like this may be a patience project. Know yeast strains don’t always follow the rules. Wild yeast and bacteria? That’s an unpredictable vector.

 

[OldDogBrewing]

Ok, I was curious if there were other factors contributing to your “unfermentable” wort. 70 is high but not outrageously high, and depending on how you got there, you may have allowed some beta amylase conversion to take place.

As far as the flour in the boil, I’m open scrutiny on this, but I’m not sure that would make your wort any more unfermentable.

In total, it sounds like this may be a patience project. Know yeast strains don’t always follow the rules. Wild yeast and bacteria? That’s an unpredictable vector.

I know it's not really unfermentable (that's why I was surprised with the attenuation), I mash like that for my English mild, and I know that this beer will take years and probably blending to be ready

My concerns are regarding to the possible presence of certain bacteria due to the low alcohol level that the beer has, basically bacterias from the enterobacter family

 

[RPh_Guy]

I was worried about all the enterobacterias that are killed ones the yeast bumps up the ABV, I know anything else is inhibited by hops or can't grow in beer, except mold but there are no signs of it

Don't heterofermenting Lactobacillus strains produce CO2 and ethanol? I didn't checked the Ph but I will do so the next time I sample it

FWIW, I suspect the gram negatives should be reasonably inhibited by the ABV even at 1%, and the low pH. They probably wouldn't be killed right away, but aren't exactly thriving. You would only need to be concerned about toxin production, which is unlikely. IMO the health risk is low, as long as it ferments eventually. I assume you don't mind taking a small risk, otherwise you wouldn't be doing a spontaneous fermentation. Enteric bacteria have been found in commercial sours, and no one has gotten sick from them.

Lactic acid bacteria do not produce a large amount of ethanol or CO2. The most they could produce is a slight fizz and you'd be able to measure ethanol production with the hydrometer, maybe 3-4 gravity points drop at most.

 

[OldDogBrewing]

FWIW, I suspect the gram negatives should be reasonably inhibited by the ABV even at 1%, and the low pH. They probably wouldn't be killed right away, but aren't exactly thriving. You would only need to be concerned about toxin production, which is unlikely. IMO the health risk is low, as long as it ferments eventually. I assume you don't mind taking a small risk, otherwise you wouldn't be doing a spontaneous fermentation. Enteric bacteria have been found in commercial sours, and no one has gotten sick from them.

Lactic acid bacteria do not produce a large amount of ethanol or CO2. The most they could produce is a slight fizz and you'd be able to measure ethanol production with the hydrometer, maybe 3-4 gravity points drop at most.

If there isn't that risk that I thought there was, I will keep it and see where it goes, I won't be brewing much on the next months due to the high temperatures so it doesn't bother me having the fermentor full

 

[henchman24]

Did you pre-acidify? What is the current pH? How are you talking the gravity readings?

If you pre acidified into the mid 4s and/or it is below the 4.3ish range now, you're as safe as it basically gets in spontaneous fermentation. One of my first 'successful rounds' of spontaneous fermentation took 5-6 months to really chew through the wort. I didn't take samples early, but judging by how the fermentation went, I'd be surprised if it was over 1-2% ABV in the first couple months.

Edit: Adding to that, many wild yeasts are not very alcohol tolerant and many don't ferment the complex sugars of wort. Entirely possible that this is all they can do.

 

[OldDogBrewing]

Did you pre-acidify? What is the current pH? How are you talking the gravity readings?

If you pre acidified into the mid 4s and/or it is below the 4.3ish range now, you're as safe as it basically gets in spontaneous fermentation. One of my first 'successful rounds' of spontaneous fermentation took 5-6 months to really chew through the wort. I didn't take samples early, but judging by how the fermentation went, I'd be surprised if it was over 1-2% ABV in the first couple months.

Edit: Adding to that, many wild yeasts are not very alcohol tolerant and many don't ferment the complex sugars of wort. Entirely possible that this is all they can do.

Today it restarted activity again, I checked for mold yesterday and it was dying out, but today it's just like any other fermentation once the krausen goes down with a lot of bubbles in the airlock

I didn't acidify the wort as I wanted to do it as traditional as I could with what I had, but I will consider it next time so I can be more sure that things are safe and I don't have to worry so much if things don't go where they should go (to have a base ABV that protects the beer)

 

[henchman24]

Today it restarted activity again, I checked for mold yesterday and it was dying out, but today it's just like any other fermentation once the krausen goes down with a lot of bubbles in the airlock

I didn't acidify the wort as I wanted to do it as traditional as I could with what I had, but I will consider it next time so I can be more sure that things are safe and I don't have to worry so much if things don't go where they should go (to have a base ABV that protects the beer)

Sounds likes a similar experience to a couple of mine. Probably a different yeast/s taking off as they build up numbers.

It is really the safest way to go, especially on a spontaneous attempt. If you get below 4.5, you're pretty much in the clear... 4.3 is definitely in the clear. There are probably some slight differences in results, but the safety (and success) factor is so much higher if you go that route.

 

[RPh_Guy]

Sounds likes a similar experience to a couple of mine. Probably a different yeast/s taking off as they build up numbers.

It is really the safest way to go, especially on a spontaneous attempt. If you get below 4.5, you're pretty much in the clear... 4.3 is definitely in the clear. There are probably some slight differences in results, but the safety (and success) factor is so much higher if you go that route.

^ I agree 100%.

Take a closer look at the process used by traditional sour brewers. Brewing -> Koelschip -> Mixing -> Straight into a used sour barrel for primary fermentation.

Going into the barrel almost certainly drops the pH right away.

 

[OldDogBrewing]

Sounds likes a similar experience to a couple of mine. Probably a different yeast/s taking off as they build up numbers.

It is really the safest way to go, especially on a spontaneous attempt. If you get below 4.5, you're pretty much in the clear... 4.3 is definitely in the clear. There are probably some slight differences in results, but the safety (and success) factor is so much higher if you go that route.

I had a hard time deciding whether or not to pre-acidify but I chose not to as I can only acidify with citric or lactic food safe acid, I didn't want to risk an off flavour, I will probably risk it next time if I can avoid all this safety concerns, and probably the off flavour isn't noticeable taking into account the complexity of an spontaneous beer

 

[OldDogBrewing]

^ I agree 100%.

Take a closer look at the process used by traditional sour brewers. Brewing -> Koelschip -> Mixing -> Straight into a used sour barrel for primary fermentation.

Going into the barrel almost certainly drops the pH right away.

Does it go sour due to the remaining sour beer in the staves or due to the action of the acid producing bacteria housed in the wood? I thought enterobacter where the first to take action in the worth, then saccharomyces and then souring bacteria and non-saccharomyces yeast (i.e. Brett)

 

[RPh_Guy]

Does it go sour due to the remaining sour beer in the staves or due to the action of the acid producing bacteria housed in the wood? I thought enterobacter where the first to take action in the worth, then saccharomyces and then souring bacteria and non-saccharomyces yeast (i.e. Brett)

I believe there's residual acid in the wood that will drop the pH to some extent. Depending on the brewery, there may be residual sour beer or trub in the barrel as well.
Yeast play an early role in lowering pH. A wide variety of non-Sacch non-Brett yeast are active very early in fermentation.
Lactic acid bacteria shouldn't have much of a direct effect early in fermentation if the hop rate is adequate.

The idea is that any pathogenic bacteria will be killed over a long term, several months. Rapid alcohol production isn't required.
My understanding is that low pH helps limit Megasphaera in particular from producing too much butyric acid, moreso than anything else.

I generally trust the info on MTF:
http://www.milkthefunk.com/wiki/Spontaneous_Fermentation#Microbial_Succession_During_Fermentation
What off-flavors were you worried about with lactic acid pre-acidification?

FYI
Enterobacteriaceae (or less formally, enterobacteria) is a family.
Enterobacter is a genus.

 

[OldDogBrewing]

I believe there's residual acid in the wood that will drop the pH to some extent. Depending on the brewery, there may be residual sour beer or trub in the barrel as well.
Yeast play an early role in lowering pH. A wide variety of non-Sacch non-Brett yeast are active very early in fermentation.
Lactic acid bacteria shouldn't have much of a direct effect early in fermentation if the hop rate is adequate.

The idea is that any pathogenic bacteria will be killed over a long term, several months. Rapid alcohol production isn't required.
My understanding is that low pH helps limit Megasphaera in particular from producing too much butyric acid, moreso than anything else.

I generally trust the info on MTF:
http://www.milkthefunk.com/wiki/Spontaneous_Fermentation#Microbial_Succession_During_Fermentation
What off-flavors were you worried about with lactic acid pre-acidification?

FYI
Enterobacteriaceae (or less formally, enterobacteria) is a family.
Enterobacter is a genus.

I was worried because I once read that dropping the PH to a great degree with acids might make the final product taste artificial

I know Enterobacter is a genus, I know it's not harmful and has been found in some Belgian lambics, not like they parents in the enterobacteria family like E Colli or anything like that, that I don't want in my beer

 

[RPh_Guy]

I was worried because I once read that dropping the PH to a great degree with acids might make the final product taste artificial

The amount used for pre-acidification is way lower than what you would need for full souring.

E Colli or anything like that, that I don't want in my beer

?? That's the point of a spontaneous fermentation. Those bacteria are in your beer, at least initially.

 

[OldDogBrewing]

The amount used for pre-acidification is way lower than what you would need for full souring.


?? That's the point of a spontaneous fermentation. Those bacteria are in your beer, at least initially.

They can be present because E Colli in theory isn't airborne in its own, I guess it can be transported through wind, so maybe it's in there or maybe it isn't, but they should die because of the alcohol and hops present, that's why I was worried about the actual low ABV

 

[RPh_Guy]

The MTF article I linked specifically mentions E. coli being found in lambic.

Totally agree that you shouldn't be worried about it at this early stage. That was my whole point here. Just let it be.

 

[OldDogBrewing]

The MTF article I linked specifically mentions E. coli being found in lambic.

Of course, but that's on their buildings, it might not be present or able to get to the wort in other specific locations, at least that's what a friend of mine with a master's degree in Food Safety told me, I usually go to him to know more about specific microbes, so E Colli can be present or not, it can be found in many places in nature, it's pretty random apparently

 

[RPh_Guy]

Yep

 

[henchman24]

I had a hard time deciding whether or not to pre-acidify but I chose not to as I can only acidify with citric or lactic food safe acid, I didn't want to risk an off flavour, I will probably risk it next time if I can avoid all this safety concerns, and probably the off flavour isn't noticeable taking into account the complexity of an spontaneous beer

I personally wouldn't use citric acid, but I don't imagine it would cause a real issue. Lactic acid in the concentration to get to 4.5 pH will be small in the complexity of a spontaneous beer... and will be one of the main acids produced by the bacteria anyway. There might be a minimal flavor difference, but it would be very hard to detect in a beer of this sort.

I believe there's residual acid in the wood that will drop the pH to some extent. Depending on the brewery, there may be residual sour beer or trub in the barrel as well.
Yeast play an early role in lowering pH. A wide variety of non-Sacch non-Brett yeast are active very early in fermentation.
Lactic acid bacteria shouldn't have much of a direct effect early in fermentation if the hop rate is adequate.

The idea is that any pathogenic bacteria will be killed over a long term, several months. Rapid alcohol production isn't required.
My understanding is that low pH helps limit Megasphaera in particular from producing too much butyric acid, moreso than anything else.

I generally trust the info on MTF:
http://www.milkthefunk.com/wiki/Spontaneous_Fermentation#Microbial_Succession_During_Fermentation

Yup... a number of modern coolship beers are really beers that get 'inoculated' in the coolship and are transferred to used barrels or foeders of some sort that will have residual yeast and bacteria. Many are not fully spontaneous.

 

[RPh_Guy]

Many are not fully spontaneous.

I'm not sure any commercial beers are fully spontaneous in the sense of being fermented only with microbes from a coolship and not also from a barrel, dregs, commercial pitch, or some form of blending.

Full spontaneous is more of a home brewing novelty ...and frankly not a good method in my opinion, because a good Brett culture is needed to "fix" all the weird yeast and bacterial products. I rarely get Brett flavors from wild cultures, so pitching one is usually a requirement in my experience. YMMV.

 

[henchman24]

I'm not sure any commercial beers are fully spontaneous in the sense of being fermented only with microbes from a coolship and not also from a barrel, dregs, commercial pitch, or some form of blending.

Full spontaneous is more of a home brewing novelty ...and frankly not a good method in my opinion, because a good Brett culture is needed to "fix" all the weird yeast and bacterial products. I rarely get Brett flavors from wild cultures, so pitching one is usually a requirement in my experience. YMMV.

Agreed, and especially so here in the US where craft breweries running these shows don't have super old buildings filled with microbes that the brewery has decades of experience with.

Yup I've never had one of my spontaneous beers ever be great on its own. Passable, and one was even good... but certainly not great. I have had success training a former spontaneous culture to create a really solid sour base... but it took generations and I'm sure the mix is vastly different than the original culture. It certainly has brett in it too that I'd almost 100% bet was floating from a random fermentation in my brew area and not from outside. That same culture has added a uniqueness to other sour cultures that has elevated them... but you're right, expectations should be low on a real spontaneous ferment. Really unlikely to get the right mix of bugs.

 

[dwhite60]

Have to ask, you are using a hydrometer and not a refractometer?

 

[OldDogBrewing]

Have to ask, you are using a hydrometer and not a refractometer?

I'm using a refractometer, but I had to use the hydrometer too as I thought the readings were wrong hahaha but they were right

 

[OldDogBrewing]

I'm not sure any commercial beers are fully spontaneous in the sense of being fermented only with microbes from a coolship and not also from a barrel, dregs, commercial pitch, or some form of blending.

Full spontaneous is more of a home brewing novelty ...and frankly not a good method in my opinion, because a good Brett culture is needed to "fix" all the weird yeast and bacterial products. I rarely get Brett flavors from wild cultures, so pitching one is usually a requirement in my experience. YMMV.

Lambics rely on the barrels really, that way they have consistent micro flora
When they buy a new barrel, they will transfer beer from a known good barrel and infect it prior to using it with wort

So probably to have a good and complete micro flora you need a couple of captures, that's why I threw a piece of wood in there, if the beer is awful (mold, high butyric acid production, etc) I will burn the piece of wood, if it's something acceptable, I will add the wood to the next batch so I can build a good culture, this might take years but once you have it, you have an spontaneous culture forever, like lambic breweries do, then it will be time to infect other pieces of wood from the best beer and have them always in the fermentors, so with time there will be differences from piece of wood to piece of wood