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05/19/08 10:51 AM  
Brett Ramblings
We talk a lot about what flavors are produced by brett, but not as much about whether these flavors are here to stay, or may go away with time.

An example: I brewed a small batch of 100% WY lambicus beer once, and it was terribly mousy. After a year in the bottle, the mousiness was gone and it was much nicer and more interesting.

The reason I bring this up is that about a month ago I bottled the first batch of beer from a new oak cask. It was a Roeselare-based red, and since I knew the oak would be overpowering in the first few batches I only aged it 6 months (and it's still way too oaky, by the way). Anyway, the important thing is that the beer has that excessive horse-manure character that sometimes rears its head when brett is present.

Looking at the table of flavor descriptions in Wild Brews, it seems that this character is more associated with the phenolic 4-ethyl-phenol (4EP) than with particular esters. (Maybe tripel beam can confirm this from his knowledge of the wine literature?) This makes some sense in light of tripel beam's statement that the precursor acids to 4EP are available from oak, and that these are new barrels.

Anyway, I am wondering to what extent this character might age out (or get worse). Anyone know? Obviously, I'll find out one way or another, eventually.

05/19/08 12:23 PM  
Re: Brett Ramblings
Baums - I had a similar experience with my first bug brew. Pretty standard, fermented all with the lambic blend, come bottling time it was pretty pissy/horsey tasting. After a few months in the bottle it was coming around, and six months away it was a pretty nice beer - it had built more acidity to balance the brett flavors. Haven't tasted it in awhile since then.....

Since that beer, I haven't experienced quite such lack-luster flavors, until the recent berliner blend weiss, which I just racked on top of 4 lbs of organic raspberries. Should be pretty tastey now, the raspberries were delicious.

05/19/08 02:50 PM  
Re: Brett Ramblings
From my own experience, I can confirm that Brett will change significantly as it ages in the bottle. My all-brett blonde was pretty offensive right after it was bottled. Like BPotts', it grew more palatable in 3 months time, and now 5 months in (I had a glass yesterday) it has really mellowed out and lost much of the pissy/horsey/mousey aromatics that were so influential in the general flavor profile. A year from now it will likely be a very good beer.

I'd say, Baums, that you'll likely have to wait longer for the oak flavor to meld and dissipate than for the brett to evolve into something less "poopy."

05/20/08 12:09 AM  
Re: Brett Ramblings
I hate to speak for Mike T, hopefully he'll respond but I have had the beer in question(though only once), but his Bourbon Brett Cherry Quad apparently was much funkier earlier on, and it faded over time. When I had it was very much playing second fiddle to the other flavors, which is not to say it wasn't an EXCELLENT beer. I'm curious about the beer now, has it continued to fade? Only one way to be sure.....send me a bottle Mike. ;)
tripel beam
05/20/08 01:12 AM  
Re: Brett Ramblings

I am still trying to figure out what Brett will eat other than sugar if anything? And what will Brett will produce other than alcohol?

As far as 4-EP, I've been exchanging emails with a lab we use, about how 4-EP reacts after bottling. I'll keep you posted Baums.

Right now I'm scared I've contaminated everything in my house with Orval/brett b. I tried to make a starter from some saison dregs and was dissapointed to find it two days later smelling identical to my Orval starter that I made 3 weeks ago.

So as they claim Burgundy, my brewery/kitchen may have "Terroir".

05/20/08 09:20 AM  
Re: Brett Ramblings
From Wild Brews: "Important by-products of brettanomyces fermentation include esterases, acids, esters, volatile phenols, and tetrahydropyridines."

I would think they have the ability to break down certain organic matter....whether they consume it or not I don't really know, but I do know that after being aged on fruit long enough, in lambic the fruit can be completely consumed down to the pits over time.

And I know what you mean about terroir...i think I can spontaneousley ferment in my upstairs closet! (envisioning a new project...)

Mike T
05/20/08 09:55 AM  
Re: Brett Ramblings
Yeah, my bourbon-cherry-brett-quad was secondaried with Brett, and definitely mellowed (in a good way) over time. I havenít had a bottle in awhile as my stores are up in Boston, so I wonít have the opportunity to try one before July.

I also noticed the mellowing with my first attempt to clone Moí Betta Bretta, it definitely had a urinal aroma when young, but after a few months it very much mellowed. In general my Brett beers seem to be harsher/rougher when young, and mellower as they age.

Give it some time, 6 months is very young for any funky beer.

05/20/08 11:14 AM  
Re: Brett Ramblings
huh--sounds like lots of people have had the mousy/urine thing and then seen it age out. Nice that there's a pattern there.

The character I have is something else--basically pure horse crap. I'm not sure I put that in the same category as the mousy stuff... but anyway I'll be patient with it and let you know what happens. tripel I'm definitely interested to hear anything about 4EP in the bottle.

Mike I agree 6 months is obviously very young--I pulled it out of the cask cause right now I'm more interested in moving batches through the cask (stripping out oak, phenol precursors, etc) as fast as possible to "mature the barrel" than I am in making each batch as good as it can be. (Hopefully these sacrificial batches are still good though, at least eventually.)

Thanks for the advice everyone.


"I am still trying to figure out what Brett will eat other than sugar if anything? And what will Brett will produce other than alcohol?"

We can get some pretty definitive answers on the eating thing. A classic academic reference for yeasts is "The Yeasts: A Taxonomic Study" which has had at least 4 editions, since the 50s. The entries on brett/dekkera include information on what brett will "eat", with and without oxygen, and what it wont. Basically brett will eat a whole bunch of complex sugars, in addition to the usual simpler ones. Some bretts will readily eat lactose, some won't, etc etc. Cellobiose is an important on cause there's plenty of it in toasted oak. The tougher question is to what extent brett will eat TRUE DEXTRINS and starch. It won't eat starch under the conditions of some tests found in academic papers (small samples, 30 days), but that doesn't mean it won't under some other conditions.

As for what brett will produce, things are less definitive but there are some hard things we can count on. Potts quoted Wild Brews: "by-products of brettanomyces fermentation include esterases, acids, esters, volatile phenols, and tetrahydropyridines."

esterases: seen this with my own eyes--brett added to secondary seemed to eliminate ethyl acetate. Also several sources note brett eliminates isoamyl acetate, and "varietal character" (esters...) in wine.

acids: no question, from several academic papers brett can make acetic when there's oxygen around. Some obscure sources indicate a little bit of lactic (maybe 500 ppm) or a lot of citric (20000 ppm?!) can be produced by certain strains under certain conditions. A mystery.

esters: brett apparently produce enzymes that catalyze the process where lactic acid + ethanol --> ethyl lactate, and this is apparently shown in one of the Leuven lambic papers, but I haven't seen it personally. More generally brett clearly produce the sweaty/goaty esters listed in the table in Wild Brews--we've all smelled or tasted at least something along these lines. The old New Belgium Biere de Mars, and the new Avery 15, are examples where there are no souring bacteria around to confuse things.

volatile phenols: whole reams of information on this one, of course. Googling "brett" and "phenols" will probably give ten thousand hits.

tetrahydropyrridines: the mousy thing. I've tasted it in 100% brett beer and it sounds like others have too...


tripel what are you making your starter in, how do you clean and sanitize it? how do you cool the starter wort?

05/20/08 11:25 AM  
Re: Brett Ramblings
Baums - horse crap on the border of a garbage-like taste/aroma? A little while back (maybe a year ago) I found that character in several lambics from different breweries/blenders...the only ones that didn't have that taste were from cantillon (and maybe lindeman's but couldn't say I had any at the time...) - perhaps there was some lambic going around that got blended in by different brewers/blenders.....anway....whatever it was, it was very off-putting....made a couple of guezes and fruit lambics almost unpalatable.
05/20/08 12:49 PM  
Re: Brett Ramblings
Not really garbage-like--I'm not trying to be metaphorical. The aroma really is almost exactly that of manure. The only commercial beer I've tasted with the character was an "off" bottle of Printemps de Silly.

BTW the bottle of Printemps de Silly that I had a week earlier, was certainly one of the best beers I've ever tasted, and had a clear brett influence.

05/20/08 12:52 PM  
Re: Brett Ramblings
I wasn't either - those beers literally had a flavor component exactly like the smell of a trash truck....

I'll have to keep an eye out for that....though I don't see many beers from Silly around here beyond the scotch ale.

tripel beam
05/21/08 01:40 PM  
Re: Brett Ramblings
Here is what I was told by ETS labs in regard to Brett in bottle.

"I don't know that 4-EP aromas dissipate over time. There is evidence in the literature that the volatile phenols can interact with other phenolic compounds in the wine. The term often used to describe this is that the 4-EP integrates with other compounds, forming new compounds. As you know there are a number of other compounds produced by Brett, including 4-ethlguaiacol, isovaleric acid, acetic acid and many others. The production of these compounds and the ratios produced are dependent upon the Brettanomyces strain, and the wine. One thing we know is that the Brett aroma evolves over time. In an older wine, the Brett aroma can change to leather or tobacco after 10-20 years in the bottle. As you know, wine is a complex matrix and many chemical interactions occur over time in the bottle. It is very difficult to predict. However, a wine that has a pronounced "Band-Aid or phenolic" aroma early on, may indeed lose that or have it diminish over time as the 4-EP integrates with other compounds' in the wine. That said, wines with massive amounts of 4-EP generally do not become palatable over the years."

"In regards to what Brett can metabolize, there are research papers published that indicate Brettanomyces can survive on ethanol as the sole carbon source as long as it has a nitrogen source. It can use amino acids, nitrogen or ammonia for the nitrogen source. The other thing to remember is that the microbial population cycles over time in the bottle. As one organism dies, it releases it's cell contents "guts" into the wine and the remaining microbes can use those contents as carbon and nitrogen sources. Most microbes have multiple, redundant metabolic pathways to acquire energy. They prefer easy food like glucose and fructose, but can utilize a large number of other carbon containing compounds for energy."

-Dr. Richard DeScenzo

E T S Laboratories

I know this is more in regards to wine, however I thought a lot of the info translates to brewing.

05/21/08 09:23 PM  
Re: Brett Ramblings
makes sense....thanks for that! Very interesting....
05/22/08 10:18 AM  
Re: Brett Ramblings
Thanks tripel. That's interesting about the 4EP and aging.

I had forgotten about the non-carbs that brett can eat... in addition to ethanol I think there's also some evidence brett can use some organic acids as a carbon source. (In fact saccharomyces can live on ethanol as well, under the right conditions.)

Also I had a nagging feeling that my post was not precise enough about the carbs that brett can utilise, so I re-read a KU-Leuven article on brett and superattenuation:

(free link... http://www.ncbi.nlm.nih.gov/pubmed/16349005?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum)

They do conclusively show that a strain of b. lambicus can utilize a wide class of sugars, dextrins, and starches. There are enzymes to do this that are both inside the cell, bound the the cell wall, and secreted out to float in the beer. However, beer pH is *nowhere near* optimum for these enzymes, which may be why the brett is very slow to utilize starches and sugars. So while the question of whether brett (lambicus) *can* use starch is not open, there's still the open question about what practical condition make this happen at significant rate.

(BTW there are still *some* dextrins that cannot be utilized by the brett.)

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