Controlling Brettanomyces flavours w/ brewing techniques

[TANSTAAFB]

BTW reading this thread sipping a Jester King Wytchmaker, smoking a Romeo y Julieta Capulet, and freezing my ass off...couldn't be happier!

 

[metic]

So if we've got his process right, I would guess that the butyric acid probably came from enteric bacteria that survived the mash and fermented some of the wort before the lacto dropped the pH.

 

[40watt]

So if we've got his process right, I would guess that the butyric acid probably came from enteric bacteria that survived the mash and fermented some of the wort before the lacto dropped the pH.

That's what I get out of it.

 

[statseeker]

Do the enteric bacteria fall asleep or die outright in lower pH? Perhaps the enteric bacteria hang out in microenvironments in the fermenting wort where the pH is higher. Then fall asleep to the bottom in colonies and the autolyzing yeast raise the pH again. The enteric bacteria wake up and continue their activity well below the areas the lactic acid bacteria are changing the environment to a lower pH. I think we're looking at the beer as one environment where its really a series of microenvironments where we are only getting snapshots of the macroenvironment. Just uneducated theories I guess.

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[statseeker]

Could explain the variability of bottles. We're bottling one microenvironment at a time. There could be more bacteria or autolysed yeast in one bottle vs. another. It could also explain why blended batches are more consistent. Only certain yeast and bacteria will remain active or reactivate to ferment the young beer I the bottle. Especially a more acidic younger beer. And you might get a more consistent mix of autolysed yeast, remaining sugar, and lactic acid and enteric bacteria during blending. Hence a more consistent flavor. More uneducated theories. Lol

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[statseeker]

Maybe beer is like the weather in a city. We see the temperature of the city. But our backyard could differ considerably in temperature from the rest of the city. Add to that shade, sun, plants, trees. Your temperature could be +-10° from the rest of the city. But in beer its food availability, pH, temperature, alcohol, etc. in the microenvironments that certain colonies of bacteria or brett can thrive in despite the macroenvironment.

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[ahpsp]

I believe enteric bacteria are killed at very low levels of alcohol. This is what makes beer a safer drink than unclean water. Enteric bacteria are no good in anything like large numbers.

 

[Oldsock]

I believe enteric bacteria are killed at very low levels of alcohol. This is what makes beer a safer drink than unclean water. Enteric bacteria are no good in anything like large numbers.

Alcohol, but pH too. Some breweries will "force" the pH to 4.5 to stop the growth of entric bacteria (especially for spontaneous ferments). Not sure if the alcohol or pH is what actually kills them though.

I think several of the comments above give too much credit to microenvironments. Certainly there is some subtle variation during fermentation. There are strains that thrive where oxygen is more readily available (say close to the surface or barrel walls). However, beer is a liquid, and thus you aren't going to have a big gradient for things like pH, especially early on while the yeast is churning things up, producing CO2 etc.

 

[trousersausage]

After reading OldSock's experiments with fast sours I've been voraciously researching (brettanomycesproject.com, sciencebrewer.com, mistakebrewing.com etc) and I hope I'm nearing a level of understanding that will help me brew a decent 'fast sour.' I'm trying to achieve both sourness, and some brettanomyces funk in a relatively short time.

There is a lot of information out there, and I've tried to consolidate what I've learnt into the following method. I invite all feedback as I try to refine my understanding.

I plan to use 30% rolled or flaked wheat (for starches), a ferulic acid rest (30 mins at 44C) and saccharification at 66C before mashout.

The majority of the wort will be boiled as usual and pitched with Wyeast 3068 @ 20C (a Pof+ yeast that can convert the ferulic acid to 4-vinylphenol & 4-vinylguaiacol).

The rest of the wort (about 20%) will be pasteurised, then soured with lactobacillus @ 44C for 2-3 days (or as required to achieved the desired pH) in an oxygen purged vessel.
I'll pasteurise the soured wort, before adding to the majority of the wort after primary fermentation has finished.

I'll then pitch brettanomyces @ ambient 20~22C (from a starter of Petrus Pale Ale and Lindemans Cuvee Rene Gueze) in a sealed fermenter to limit oxygen.

The brett will be pitched at ale pitching rates to encourage cell growth in the low sugar/high starch environment, and I hope that they'll have the right conditions to convert the 4-vinylphenol & 4-vinylguaiacol to the classic brett compounds of 4-ethylphenol (bandaids, stables) & 4-ethylguaiacol (smoky, spicy) in a relatively short period of time (2 months maximum).

Thoughts/feedback?

 

[tagz]

Look forward to the results.

 

[dantheman13]

After reading OldSock's experiments with fast sours I've been voraciously researching (brettanomycesproject.com, sciencebrewer.com, mistakebrewing.com etc) and I hope I'm nearing a level of understanding that will help me brew a decent 'fast sour.' I'm trying to achieve both sourness, and some brettanomyces funk in a relatively short time.

There is a lot of information out there, and I've tried to consolidate what I've learnt into the following method. I invite all feedback as I try to refine my understanding.

I plan to use 30% rolled or flaked wheat (for starches), a ferulic acid rest (30 mins at 44C) and saccharification at 66C before mashout.

The majority of the wort will be boiled as usual and pitched with Wyeast 3068 @ 20C (a Pof+ yeast that can convert the ferulic acid to 4-vinylphenol & 4-vinylguaiacol).

The rest of the wort (about 20%) will be pasteurised, then soured with lactobacillus @ 44C for 2-3 days (or as required to achieved the desired pH) in an oxygen purged vessel.
I'll pasteurise the soured wort, before adding to the majority of the wort after primary fermentation has finished.

I'll then pitch brettanomyces @ ambient 20~22C (from a starter of Petrus Pale Ale and Lindemans Cuvee Rene Gueze) in a sealed fermenter to limit oxygen.

The brett will be pitched at ale pitching rates to encourage cell growth in the low sugar/high starch environment, and I hope that they'll have the right conditions to convert the 4-vinylphenol & 4-vinylguaiacol to the classic brett compounds of 4-ethylphenol (bandaids, stables) & 4-ethylguaiacol (smoky, spicy) in a relatively short period of time (2 months maximum).

Thoughts/feedback?

Cool experiment! What is the thinking behind heat pasteurizing the soured wort?

 

[metic]

Sounds like an interesting experiment, I'll be curious to hear the results! I have a couple of questions.

Why do you think that pitching the brett at ale pitching rates will encourage growth? And what do you mean by ale pitching rates, I guess? Are you going to pitch relative to the amount of gravity points left after fermentation? Or according to the O.G? Either way, I wonder if pitching fewer cells wouldn't be more likely to encourage growth. Pitching at ale rates for a secondary fermentation seems like pitching a lot of cells. (But I'm also unclear on the extent to which brettanomyces flavour contribution in secondary is related to growth/reproduction?)

Also, if you're deliberately creating a dextrinous/starchy wort, there's no reason to think the brett will be done fermenting it in just two months, even if the beer has started to taste funky. So if you're looking to turn this around quickly, you would probably have to keg rather than bottle condition, or at least store the beers cold to stop further fermentation.

One last thing to keep in mind: even if the beer is both sour and funky after two months, there's no guarantee that these flavours will complement each other in a way that's pleasant. Its pretty easy to brew a beer that gets sour and/or funky quickly---a lot of the waiting is for these flavours to meld/mature, and if they were created too quickly they might end up getting more unbalanced over time as the phenols increase, rather than blending. Then again, I don't really like beers in which the more phenolic character from brett is dominant, but your palette may be different!

 

[trousersausage]

Great feedback guys. I certainly don't have all the answers, but I'll try to respond.

@dantheman13

I'm souring the wort with lactobacillus purely for the lactic acid. Once an appropriate level is achieved I'll pasteurise to lock in that level of sourness. Also, I'll probably inoculate with the lactobacillus found on raw grain, which could also introduce other organisms that I don't want in the final beer .

@metic
I had the same thoughts about pitching rates. I think that, as with saccharomyces cerevisiae, the growth phase is important with Brettanomyces. This study discusses the effects:
3.1 Impact of growth phase in the nonculturable B. bruxellensis population
and 4-ethylphenol production
http://run.unl.pt/bitstream/10362/10986/1/Fernandes_2013.pdf

In summary, cells produce 4-ethylphenol (4EP) at all stages, but when there is a long lag time (time between pitching and cell growth) there is a decrease in overall 4EP production. Cells in the exponential phase, as well as healthy stationary cells (after lag phase and growth phase) are effective producers of 4EP.

So it seems that pitching rate is important, and that it is important to create healthy cells that are adapted to their environment, just as with saccharomyces. When I mentioned ale pitching rates, I guess I mean relative to the gravity after primary fermentation. I use usually use
http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/
to determine my pitch rates.

In terms of the right conditions for growth, somewhere around 25C seems to be a good temperature (higher might be better, but that's pushing into unconventional territory), and I don't have enough experience with dextrinous/starchy worts, or Brett, to know if two months is enough time for fermentation, but and if I can optimise the conditions I'm certainly giving the yeast the best chance.

My thoughts are that traditional lambic fermentations take such a long time as the conditions for Brett aren't ideal at the outset, and it takes time for the (potentially) unhealthy Brett to produce the enzymes to produce 4EP & 4-ethylgluaiacol (4EG).

If I can optimise the conditions from the outset by
a) providing a starchy wort (which saccharomyces can't process, and will be available for the Brett after primary fermentation finishes)
b) providing an abundance of 4-vinylgluaiacol (4VG) & 4-vinylphenol (4VP) and relatively little ferulic acid (which inhibits Brettanomyces growth, and which weizen yeast converts to 4VG & 4VP)
c) providing hydrocinnamic acids (including ferulic) for the weizen yeast to convert by using an acid rest at 44C
d) providing oxygen to allow initial growth (but limiting oxygen thereafter)
e) keeping the temperature around 25C
f) keeping ethanols levels relatively mild (ethanol inhibits growth, with growth ceasing above 15% v/v)

I initially thought that pH played a big role, but unless the pH is <3.5 I think it makes little difference, which makes sense as (from memory) Orval isn't very acidic yet it has definite Brett characteristics.
http://www.researchgate.net/publica...n_red_wine_making/file/79e4151278ac1f0594.pdf
Effect of free SO2 at pH 3.5 on the conversion of p-coumaric acid into 4-ethylphenol
In summary, low pH = higher levels of SO2 which increase the inhibitory effects of benzoic and sorbic acids.

I've also thought about beers that are 100% Brett fermented and why they don't end up especially phenolic. I'm guessing its because Brett isn't effective at converting hydrocinnamic acids (including ferulic) into 4VG & 4VP, but I don't have the science to back that up.

As you point out, whether this turns out pleasant or not is a whole other story. Science aids brewing, but in the end it's your tastebuds that decide!

 

[metic]

Nice, looks like you've done your research. I'm looking forward to reading those papers tomorrow.

I guess one thing I meant to be saying is that you're focusing a lot on the production of phenols, and that isn't the only thing people look for from Brett---in fact, some people try to minimize them (e.g Chad Yakobson). So you want to be sure that those are the flavours you want, or at any rate want to maximize.

 

[Failing_Ales]

you are taking steps to have lacto-produced acidity without leaving live bacteria, but then plan to pitch a mixed culture that will include brett, lacto, and pedio? Or do you mean that you will pitch a brett isolate from cuvée rene?


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[trousersausage]

@Failing_Ales

I'd kind of glossed over the fact that bottle dregs are a mixed culture. You're right, I will be introducing pedio and lacto (again) and I could do some research into the effects they will have. I doubt they'll have a great effect in a short period of time as I expect Brett to be the dominant organism, but it's definitely something to look into.
As for not leaving live lacto bacteria, the sour portion of the wort will have a lot of healthy, active lacto that I don't particulary want working on the majority of the wort. I think that introducing a small amount of lacto from a mixed culture will have a relatively small impact (especially in the presence of dominant Brett) compared to introducing a large amount of pure lacto (and possibly acetobacter).

 

[trousersausage]

For anyone that is interested...

 

[trousersausage]

After more research I'll admit that I underestimated the contribution of the lactic acid bacteria lactobacillus and pediococcus in beer flavour. I don't have a science background, but I'm enjoying learning about the biological processes that happen in beer and thanks to access to academic databases, I'm able to access some interesting articles.

 

[trousersausage]

In summary, whilst Brettanomyces is very effective at producing esters and phenols, lactic acid bacteria also contribute these compounds and favoured their growth conditions are similar: pH<7, temperature>20C, low oxygen environment.
I haven't considered any of this when I pitched bottle dregs in favour of a pure Brett strain, but in light of the positive effects these bacteria can have, I'm glad I did.

 

[loftybrewer]

OK just spitballing here, but reading few lines of that article made me think of...Chardonnay. Why do you ask? Great question! Well, Chardonnay traditionally undergoes a malolactic fermentation, during which lactic acid is transformed into - you guessed it, malolactic acid, which is generally reported as being much less sour in taste. Often you will get notes of pear, apple, peach, pineapple, grapefruit, melon, etc. Sound like the tropical esters that folks like Chad and sausagepants are working for? Well, that last article mentioned that malolactic fermentation results in an alteration of the ester profile.

"Researchers observed increases in ethyl ester concentration in wine following malolactic fermentation, including ethyl acetate, ethyl hexanoate, ethyl lactate, and ethyl octanoate, as well as decreases in some esters...Changes in ester concentration following malolactic fermentation may either enhance or degrade wine quality, depending on the ester metabolized."

It's not specific. However, perhaps messing with the lactic acid production and then doing a malolactic fermentation (softening the sourness) might set the stage for certain brett strains to do some interesting things? Also, Chardonnay is traditionally aged in oak. Maybe I'm not making sense but I see some parallels between Chardonnay and mouth-explosion brett beers all of us funkmeisters would love to create. Just a thought

 

[metic]

Interesting, but I'm a bit confused: I thought malolactic fermentation transformed malic acid into lactic acid? So you would want to produce a wort high in malic acid rather than lactic acid. In fact, the reason for the increase in those esters might just be that there is now more lactic acid present to be a precursor to them, which should be there anyway in a sour beer?

 

[BzurkoBrews]

That's what I thought too.


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[dantheman13]

Interesting, but I'm a bit confused: I thought malolactic fermentation transformed malic acid into lactic acid? So you would want to produce a wort high in malic acid rather than lactic acid. In fact, the reason for the increase in those esters might just be that there is now more lactic acid present to be a precursor to them, which should be there anyway in a sour beer?

That's what good old Wikipedia says: http://en.wikipedia.org/wiki/Malolactic_fermentation

I think Lofty accidentally got that backwards (or Wikipedia is wrong).

 

[Oldsock]

OK just spitballing here, but reading few lines of that article made me think of...Chardonnay. Why do you ask? Great question! Well, Chardonnay traditionally undergoes a malolactic fermentation, during which lactic acid is transformed into - you guessed it, malolactic acid, which is generally reported as being much less sour in taste.

Sounds like you were guessing. Malolactic fermentation turns malic acid (contributed by grapes, apples, and several other fruits) into lactic acid. Lactic acid is actually the "softer" acid compared to malic. In wines an Oenococcus oeni culture is pitched with completes the malolactic fermentation even with high alcohol and low pH. However, the same type of fermentation can be done by many of the strains of lactic acid bacteria already found in sour beer (if you are adding malic-acid containing fruit).

 

[loftybrewer]

You're right, that was all based off of my assumption that malolactic went the other way 'round. No point in adding wlp675 to my brett beers. However, if that conversion can set the stage for brett to go juicy-fruit wild, then I for one will be requesting a couple gallons of wine varietal grape juice from local wineries this harvest season for my brett beers!

 

[trousersausage]

@oldsock

any thoughts on the 4VG -> 4EG pathway that I described by fermentation with a wheat yeast then brett?

anything to add regarding the flavour development and ideal conditions for Lactic Acid Bacteria (LAB), especially pedio?

 

[Oldsock]

@oldsock

any thoughts on the 4VG -> 4EG pathway that I described by fermentation with a wheat yeast then brett?

anything to add regarding the flavour development and ideal conditions for Lactic Acid Bacteria (LAB), especially pedio?

It does seem that fermenting with a phenolic primary yeast increases the funky character of the finished beer. The only issue is that esters/phenols aren't a 100% thing, so likely you still have a beer with some banana and clove even after extended aging, which you may or may not want.

Pedio prefers low oxygen. I don't buy that either plays a huge role in flavor development on their own given the character of 100% Lacto and Lacto/Sacch beers I've brewed and tasted. It is more likely that the pH lowering and lactic acid they supply make for more interesting character from the Brett. Chad Yakobson did some interesting work on the effect of pH on ester production, it helps some and hurts others.

 

[trousersausage]

Let the experimenting begin.

 

[unclebrazzie]

Alright, let's do this.
I have a batch of seriously offensive Gose. 2/3 wheat malt, 1/3 pilsnermalt with just a splash of acidulated malt.
The wort was intentionally soured before boiling by pitching with a bottle of geuze and letting it go its course for 36hours in a hot room (approx 25° to 30° C). That proved too cold: I got a massive stinkbomb of butyric acid which I boiled (stunk up the place something fierce) and is now nearing the end of primary fermentation (Mauribrew 514). Post-boil, the sell had dissipated (read: leeched into my house) and the brew tasted quite okay.
Now with primary almost ended, the butyric acid is coming back into the mix. Not pleasant.

Reading all the above, combined wit various other sources of input, it would seem that my last hope is Bretts, which might be able to turn the bileous butyric acid into more savoury butyrate esters.
So I'm going to rack to secondary sometime soon, pitch with a pack of WLP644 (Brett brux) and leave things in the cellar for a few months. Should be stressfull enough for them to not try anything orthodox and munch on all those juicy by-products.

I will of course report back as soon as I've learned anything from this, other than "butyric acid in beer = dump it".

 

[JF_HBrews]

You're right, that was all based off of my assumption that malolactic went the other way 'round. No point in adding wlp675 to my brett beers. However, if that conversion can set the stage for brett to go juicy-fruit wild, then I for one will be requesting a couple gallons of wine varietal grape juice from local wineries this harvest season for my brett beers!

I'm confused, why the grape juice? Are you expecting spontaneous/wild maloactic fermentation? If not, wouldn't any sugary fruit do?