Brettanomyces, Pellicles, & Oak Barrels

As noted in this previous thread (Oak Barrel - 20L) I acquired an oak barrel to age half of my Winter Warmer ale this year to give it that Extra Special Reserve kind of a kick.

Well it appears, using the oak barrel, I got more than I bargained for!


Brett Pellicle?

This year I did a 10 gallon batch of my winter warmer. 5 gallons got the normal treatment, bottling, and are currently aging. The other 5 gallons instead of going to the bottle spent an extra week in the oak barrel, and then last Sunday were racked to my secondary.

Well, yesterday (Tuesday night) I took a look and the secondary now has a white milky film across the top (Brettanomyces Pellicle?). I then took a sample of the film and inspected it in the microscope expecting to find bacteria and a lost batch of beer. To my surprise it wasn't bacteria at all. It appeared relatively the same size as yeast cells, only sausage shaped instead of round like a yeast cell. It was much larger than bacteria, and contained a nuclei so I can pretty much be assured it's not bacterial and is indeed a Eukaryote (see budding yeast cells in image).



So, that got me on my search to which I found this in the homebrew wiki.

Brettanomyces, often called Brett for short, is a genus of yeast consisting of multiple species found naturally in wood. Brettanomyces contributes distinctive flavors to the beverage it grows in. It gernerally considered an undesirable, spoiling infection by home brewers; however, its extreme, distinctive flavor and aroma is considered desirable in some sour beer styles, and at low levels it is depended on to add complexity to many styles of wine.

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Wikipedia adds;

The cellular morphology of the yeast can vary from ovoid to long "sausage" shaped cells. The yeast is acidogenic and when grown on glucose rich media produce large amounts of acetic acid. Brettanomyces is important to both the brewing and wine industries due to the sensory compounds it produces.

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Since my winter warmer is indeed a sort of spiced up brown ale, I figured I'll roll with it and see how it turns out. I have put a previous batch (another brown ale) through the barrel already, and the same thing happened, though I ignored it as a mild infection and bottled it. The Brown was a little sour, and very complex, and actually pretty good after it aged a few months.

I went ahead, and just sanitized the barrel really well with Potassium Metabisulfite and let that sit for a few months prior to my Winter Warmer figuring that would be enough to pretty much kill anything. Apparently it doesn't kill Brettanomyces in the dosing regiment I used (1/2tsp Potassium Metabisulfite per 5 gallons) like it does normal yeast and bacteria.

So any sour beer experts want to give me a primer on what to do next? Do I rack this into the keg or bottle and hope for the best? Is there a technique for dealing with Brettanomyces and Pellicles? Input and comments are welcomed! Should be an interesting result.

Have you tasted a sample yet? How does it smell? I'm no sour beer expert (although I'm brewing my first Brett amber ale now, a DeKonnick clone), but this is a unique beer and I think you should let it roll.

It sounds like you have some brett and other various goodies on your hands!!! It likes to reside on porous surfaces like wood. I'd let it go and see what happens.

Ya, once a porous wood barrel is infected with yeast or bacteria they'll always be there (in some concentration). Consider it a gift and make some awesome "horsey", "oaky" beers.

People will pay big money for a brett infected oak barrel. They are great for long term aging as a secondary - it gives off a less sour taste.

OK at lunch I got some better pics (see origional post) and got a 25ml sample to try.

Smell is normal, alcohol (it is near 9% after all), oak, special spices, wintery, a hint of sourish-ness but not harsh. Overall, nothing taste or smells out of whack, pretty much like I expected it to taste.

So cool, well see how it ends up!

Any clues on how to rack this off? Just try and avoid pellicle? How long should I let it age like this?

Dont touch it for awhile, unless you were intending to drink it this winter. If you bottle that and leave it till next winter you will thank me...................I am one that would pay for a brett infected oak barrel.

If you do rack it soon just stick the cane through the pellical and stop just before you suck up some of the white crud.


lucky!:rockin:

i was under the impression that the pellicle will reform in the bottles if you bottle before its dropped?

scinerd3000 said:

i was under the impression that the pellicle will reform in the bottles if you bottle before its dropped?

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I'd like to know the answer to this as well, as I am brewing a brett-fermented amber right now. Is there any difference to the racking/bottling/slurry collecting/yeast washing procedures?

In my experience a pellicle can/will still form in the bottle with Brett. beers.
There's not much difference in R/B/SC with Brett. I haven't tried washing it though seeing that all you need to infect your next batch is a very small amount. Unless, of course, you are fermenting the entire batch with Brettanomyces. I usually just pitch a whole slurry, and let it go to town. Made some fantastic beers this way. Actually did a beer swap on another HB forum where we all brewed different beers, but they all had to be fermented with only Brett. Out of the 10 beers, only one actually had the stereotypical "horseblanket", "goat scrotum" Brett. flavors. One of the best Belgian Golden Strongs I ever had was from that swap.
Anyway, back to the funked up winter ale. You can still drink it young and not get much Brett. flavor from it, but anymore than a month or two you will start to notice. That's not a bad thing in my opinion..
I do agree that you should let this one age and let the bugs work thier magic. They can do some wonderus things if left alone.
As to the barrel, try a Flander Red, or a good Belgian Farm house and age in your barrel. You'll be the envy of the block with the love that comes out of that barrel.

scinerd3000 said:

i was under the impression that the pellicle will reform in the bottles if you bottle before its dropped?

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From what I've read, the pellicle forms as a natural protection from oxygen to support anaerobic activity. So, once bottled, a pellicle won't form unless you leave a very large amount of headspace and/or your bottles are made of something porous (e.g. wooden bottles ).

Also when you clean that carboy, use iodine, not starsan. Brett can stand the acidity of starsan just fine.

z987k said:

Also when you clean that carboy, use iodine, not starsan. Brett can stand the acidity of starsan just fine.

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Now that, that is a great tip, and should be somewhere prominent.

Where are you getting this info z987K, about iodine?
I've found the exact opposite to be the case.

lamarguy said:

From what I've read, the pellicle forms as a natural protection from oxygen to support anaerobic activity. So, once bottled, a pellicle won't form unless you leave a very large amount of headspace and/or your bottles are made of something porous (e.g. wooden bottles ).

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I think thats somewhat of a myth. From what I've been reading in "Wild Brews", it forms the pellicle to get to the ambient oxygen and to protect from other wild bugs that may want to get at the beer during a typical open fermentation.

I have no real experience, but everything I've read says to leave it with the brett for at least 6 months. If your beer is fermented, it will take a long time for the brett to work since there is very little for it to eat. It is also a superattenuative yeast. That means it will continue to break down the more complex sugars like maltotriose that the saccharomyces cerevisiae couldn't. At this point, you won't get a super funky beer.

z987k said:

Also when you clean that carboy, use iodine, not starsan. Brett can stand the acidity of starsan just fine.

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Really? I read the opposite, that StarSan would kill brett but Iodophor would not.

Natas said:

StarSan is your best bet to help kill off the bugs. Iodophor doesn't kill off Brett, or Pediococcus.

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So I'm confused. The only thing I've seen as a reference is that the Wikipedia page says that Sulphur Dioxide (S02) is known to kill it, but that is a gas, so not sure how you would use it.

I've been really questioning sanitizers lately, and have been wanting to do a test (vs) Iodophor, StarSan, Potasium Metabisulfite, and Bleach. I might do that when I get my autoclave.

Edcculus said:

I think thats somewhat of a myth. From what I've been reading in "Wild Brews", it forms the pellicle to get to the ambient oxygen and to protect from other wild bugs that may want to get at the beer during a typical open fermentation.

I have no real experience, but everything I've read says to leave it with the brett for at least 6 months. If your beer is fermented, it will take a long time for the brett to work since there is very little for it to eat. It is also a superattenuative yeast. That means it will continue to break down the more complex sugars like maltotriose that the saccharomyces cerevisiae couldn't. At this point, you won't get a super funky beer.

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Well, the batch I'm making is an LHBS recipe, and I trust the owner. He's said to treat the timing like any other ale, and says the beer has turned out just great. So no 6 month wait for me.

StarSan will kill Brett just fine.

The yeast will try to reach metastasis with their environment and internal cell pH ~ 7.4 along with external cell pH ~ 3 = cell wall kablooey.

PseudoChef said:

StarSan will kill Brett just fine.

The yeast will try to reach metastasis with their environment and internal cell pH ~ 7.4 along with external cell pH ~ 3 = cell wall kablooey.

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Precisely,
Iodine (Iodophor) reacts with anything organic. That is how it kills bacteria. But it can not penetrate the protective coating that protect a bacteria spore. So the mature cells die, but the spores live on to infect further batches. Star San has a wetting agent ( the dreaded foaming action, or surfactant) that softens the cell walls of bacteria and the protective coating. Once softened (via the low pH) the phosphoric acid ruptures the cell wall killing both mature cells and spores.

Starsan will kill anything that can infect your beer. The notion that acid environment won't kill brett is false, as commercial wineries use citric acid and sulfur dioxide to control it.

well I'm off to confirm with a technical document of some sort to confirm what you guys are saying. I've been told by a brewer I trust a lot that starsan doesn't kill brett. I've always gone with bleach when battling it though.

On another note, do get a oak dowel in that carboy to let some O2 seep in.

Yah, just to be safe, I'll probably bleach out my fermenters that I use for Brett.

z987k said:

On another note, do get a oak dowel in that carboy to let some O2 seep in.

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Really? So you want oxygen? Could you also just add a foam stopper instead of an airlock?

At this point this batch is entirely for experimentation, I prefer it end up something desirable, as the SWMABO would prefer it.

Deofol said:

Really? So you want oxygen? Could you also just add a foam stopper instead of an airlock?

At this point this batch is entirely for experimentation, I prefer it end up something desirable, as the SWMABO would prefer it.

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Here's a real good page on the subject of sours.

Brewing Flemish Red Ale, by Raj B. Apte

FTA:

5. Pellicles. Pellicles are an indicator of headspace oxygen. Brett, Acetobacter, and other pellicle-forming bugs do so when the headspace of a container is oxygen rich. I don't understand the considerations between headspace and dissolved oxygen entirely, but too much headspace oxygen can result in too much acetic acid formation. Dissolved oxygen feeds Brett, but too much of it can oxidize the taste of the beer. Maltiness can be lost.



Bretta likes to form pellicles and is very efficient in this mode. Pellicle formation may depend on the presence of gaseous O2. Although all Brettanomyces exhibit the Custer effect (aka negative Pasteur effect), it is unclear if different flavour compounds are produced in aerobic or anaerobic conditions. Anecdotally, people complain of lack of complexity in pure culture lambics that are aged in glass. I take this to suggest that Brettanomyces should be grown aerobically, and that pellicle formation may be important for allowing additional oxygen into the system and accelerated Bretta production of flavor compounds. This is purely speculation at this point, but its consistent with the Acetobacter/Brettanomyces mixed pellicle observation (vs).

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I found a good paper that describes the ethanol and acetic acid production from Brettanomyces in oxygen rich and oxygen poor environments.

They found that in an oxygen rich environment, the acetic acid production was higher than in an oxygen poor environment. Acetic acid is the primary byproduct of Brett, so this supports the theory of long fermentation in porous substrates (e.g., wood barrels, plastic containers, etc.) to provide a source of oxygen and, consequently, develop maximum Brett "flavor".

For 1 and 2 g l–1 acetic acid concentration,
total substrate consumption for aerobic and aerobic
conditions can be seen; under aerobic conditions, there was
high ethanol production and biomass growth, and in the
anaerobic case, their values increased considerably. For the
kinetics with acetic acid concentrations over 2 g l–1, substrate
consumption was not total. Ethanol production and
biomass growth decreased, but acetic acid remained constant
when there was no oxygen, and increased under
aerobic conditions.

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Get a copy of Jeff Sparrow's "Wild Brews". He has almost an entire chapter devoted to brett (how it grows, produces, what it eats etc).