Reduction of Butyric Acid / Conversion to Ethyl Butyrate?

Trying to make a long story short(er):

I started fermenting a Centennial / Nelson Sauvin hopped Saison (French Saison strain) for a few days and when the gravity dropped to about 1.025, I pitched a mixture of non-commercially available Brettanomyces strains.

The Brett was obtained from the bottle dregs of several of Chad Yakobson's beers (Crooked Stave/ BrettanomycesProject.com). I made a 2 liter starter on a stir plate for about a week to get a good population of Brett- don't forget that these are originally 100% Brett beers so they have more cells than you'd expect. This is kind of halfway between a 100% brett beer and Brett under extended aging.

My problem is that the Brett has produced HUGE quantities of Butyric acid (Bile / Vomit); some of Chad's early beers had this problem and all of them still have quit a bit of butyric as a background note (depending upon how sensitive you are to it).

What can I do to reduce the Butyric Acid content / convert it to Ethyl Butyrate (pineapple) now?


Is this just a matter of leaving it for months and months?
Do some Brett strains convert Butyric faster?
Does a Brett "Krausen beer" help with Butyric reduction at all?


I've reached out and asked Chad the same questions but now I'm kind of wishing I would've used a different Brett strain / only pitched for extended aging after the gravity reached 1.010 or lower...


I've got some great hop flavors in here but right now they're on top of vomit flavors. If I can get some pineappley ethyl butyrate on top of Centennial+ Nelson Sauvin I could have something truly great, I'm just not sure science has figured out how to control butyric acid to ethyl butyrate conversion yet...



Open to any and all ideas right now as leaving my vomit beer for a year to hope that it stops being vomit beer doesn't really give me a lot of hope.


Adam

Ethanol and butyric acid react to form ethyl butyrate with the elimination of water:

EtOH + HBut ---> EtBut + H20

but as the reaction in the laboratory would be carried out in the presence of hot sulfuric acid (sucks up the water thus pushing the reaction to the right) I have some doubts as to how fast it would take place in cold beer, if at all, unless some enzyme catalyzes it. Wait and see seems like the best approach.

Brettanomyces has the enzymes necessary to take us down this pathway, for sure.

But my understanding is that naturally its a slow and steady conversion and isn't super efficient and doesn't get rid of all of the butyric.

My best guess is that higher ethanol levels will help the esterification and will reduce more butyric acid.

What I don't know is whether certain brett strains are better at this reduction, like certain yeast strains are better a diacetyl uptake and conversion.

I also don't know whether this process is best facilitated under anerobic or ever so mildly aerobic (slow amounts of oxygen as you'd get through extended barrel aging). I don't know whether the Brett needs to be deficient of other nutrients before it will choose to go down this pathway.

Is this something that would be accelerated by pitching a Brett krausen beer?

Is this something that's accelerated at higher temps even when facilitated by Brett enzymes? (I'd probably guess so as most reactions are accelerated with heat, right?)


I'm hoping Chad responds to my email; I know his beers have had problems with butyric and these are his brett strains we're dealing with. My hope is that as a production brewery he's having to deal with balancing production schedules and butyric levels and if I just leave it for a long time on the Brett, it will take care of cleaning up most of the butyric.

The best thing about hoppy brett beers is that they scavange oxygen incredibly well and keep that fresh hoppy flavor around for a quite so time, so if extended aging is the case I'll just dedicate this fermenter to this experiment for a while.


Adam

Mo Betta Bretta is something of the holy grail of Brett beers due to it's reputation for a very pineapple-like flavor, but no one, Chad included so far, has been able to replicate it at all consistently.

I'm hoping that I'm just one step away given all the butyric acid precursors that my beer currently has. ;-)
http://www.beeradvocate.com/beer/profile/18149/82143/

Adam

Hmm... Looks like Chad measured basically everything except butyric levels for his master's dissertation. *Sigh*

Ethyl acetate, ethyl lactate, total ester compounds, total higher alcohols, vinyl phenols, vicinal diketones, attenuation, fermentable sugars, ethyl lactate, ethyl acetate, ethyl caproate, ethyl caprylate..

Even Ethyl Butyrate but the levels where low in his conditions; and again, I'm looking for Butyric levels, not Ethyl Butyrate.


Dang...
http://www.brettanomycesproject.com/




Adam

Yeah I've got the same questions. Particularly if certain brett strains/amounts/conditions are better at handling butyric to ethyl butyrate transformation.

I'm in a similar situation with an incredibly butyric beer that came out of a sour mash. I pitched 1L/5gal Brett B (wlp650) a few days into fermentation, and its been sitting around for 6 months already. Still smelled and tasted pretty enteric a few months ago.

I'll find out what they do at Lost Abbey whenever they get a "sick" barrel. They're pretty friendly over there.

It sounds like they just like to wait it out with whatever is living in the barrel (lacto, pedio, bretts), rather than do any specific additions.

They seem pretty stoked on the butyric: "Congratulations on the butyric. That is awesome! We love those because we know that they will eventually be lovely tropical fruit." Though that can take as long as 2 years. Also "the sickness" can die down and then bloom back up, but that just means you have super healthy cultures.

Their recommendation is if you think that the beer still seems ok, just wait it out and you'll probably end up with something good.

I could be wrong but I thought that "sickness" in the lambic tradition refers to "ropiness" that comes from the slow work on pediococcus.


My butyric faded rather quickly so, I think that means that my sense of taste just isn't properly calibrated yet. I need to go back and do the butyric taste standard again because apparently I've forgotten it already. Now I've just got a very "bretty tasting" beer.

I have to say that the combination of Centennial and Nelson Sauvin really contribute to a generally pineapply thing going on. I probably should've got with a more assertive hop variety for this beer but I still like it.


Adam

biertourist said:

I could be wrong but I thought that "sickness" in the lambic tradition refers to "ropiness" that comes from the slow work on pediococcus.


My butyric faded rather quickly so, I think that means that my sense of taste just isn't properly calibrated yet. I need to go back and do the butyric taste standard again because apparently I've forgotten it already. Now I've just got a very "bretty tasting" beer.

I have to say that the combination of Centennial and Nelson Sauvin really contribute to a generally pineapply thing going on. I probably should've got with a more assertive hop variety for this beer but I still like it.


Adam

Click to expand...

That is awesome. Glad you got a good result. I'm jealous! :cross: How long did you end up waiting until it all cleared up?

Sam_B said:

That is awesome. Glad you got a good result. I'm jealous! :cross: How long did you end up waiting until it all cleared up?

Click to expand...

It was like 5 days from the peak of grossness until it's current state... -Yet another reason I'm thinking it wasn't actually butric acid but generally early Bret fermentation stinkiness. (That's what Chad thought, anyway and I'm starting to think he was right.)


Adam

I don't think it was Brett that produced the Butyric Acid but bacteria. Either way time is your friend. Given enough time Brett should clean it up.

A bit older thread, but I have the answer to the cliff hanger!

Clostridium bacteria produces the butyric acid in the first place. Clostridium thrives at about 90-120F, so anytime the wort is going to be in that general range for any extended period of time, you have to be careful that no oxygen is present to discourage the bacteria. This includes making sure to purge the headspace of the fermenter with CO2 pre-fermentation.

Even better, if you are intending to make a tart beer anyway, you can also add about 5ml of lactic acid per 5 gallons to the wort to get the PH down to 4.5, at which the Clostridium can not survive. This also necessitates proper pitch rates, oxygenation, and a bit of yeast nutrient for all around good yeast health so that your saccromyces can overcome the lower PH as well. Bad yeast health conditions + 4.5 PH = no fermentation!

Hope that helps! I used to have this problem with my Berliners, and completely eliminated the butryic acid with the two processes above!