Friday, June 6, 2008

All about Brettanomyces

Greg Doss from Wyeast is putting together a presentation on brewing with Brett and asked if I could answer a few practical questions on my experience brewing with Brettanomyces. I thought this would be a good post to combine many of the bits of info that are scattered all over my blog into one spot. Most of these topics are fleshed out in more detail on other posts, but I'm too lazy to put in all the links at the moment.


Interview – Michael Tonsmeire – Mad Fermentationist


How do/have you use(d) Brett?
What beers?
Old Ale (Brett C in secondary),
Belgian Strong Dark with Cherries (Brett C and Orval dregs-Brett B in secondary),
Courage Russian Imperial Stout Clone (Brett A in secondary),
2 Flanders Reds (Roeselare Blend in secondary for one, US-05 plus a starter grown from the dregs of a bottle of Lost Abbey's Red Poppy in the primary for the other),
Flanders Pale (wood from first Flanders Red plus Russian River Depuration dregs in secondary),
Lambic (Wyeast Lambic Blend in primary),
Temptation Clone (Russian River inoculated chips in secondary, ~4 strains of Brett plus all sorts of other microbes),
Berliner Weisse (3191 Berliner Blend in primary)

I have also played with sourdough cultures and kombucha to ferment wort, both of which probably contain some Brett, but I can’t be sure.

Brett only?
2 Low-Gravity Saisons (one Brett C and one Brett A),
2 Mo’ Betta Bretta Clones (one Brett C and one Brett A, each batch was split with half getting sour cherries and pinot noir),
Brett Pale Ale (Brett A)

Co-inoculum? What other strains? Multiple strain antagonism or cooperation?
I have not used multiple Brett strains in a primary fermentation, but in secondary they seem to cooperate between strains and with other microbes as far as I can tell. Russian River Sanctification is the only commercial beer I know of that uses two strains (L and B plus some lacto) and it is delicious.

Inoculation rate?
For 100% Brett beers I inoculate at about the rate I would use for a lager, which is a pretty healthy pitching rate. It can take awhile to build up a culture to this volume, but it an be done is a stepped up starter like a standard ale yeast. If growth seems to slow down some chalk can be added to buffer against any acidity created by the Brett.
For secondary fermentation a small amount of Brett is fine, but the more you pitch the faster you’ll get results because growth is very slow in such a stressful environment (alcoholic, low pH, no simple sugars, etc…)

Inoculation Timing (When)? Pre-primary, Co-inocualte, Post-primary, @Bottling
I generally pitch the Brett into secondary after the Saccharomyces fermentation is finished, this gives me more control over the end results because I give the Brett a set amount of carbohydrates to eat. I have played around with pitching in primary along with Saccharomyces and bacteria, in general these beers are funkier/sourer because the Brett and bacteria has more time to grow in a low-stress environment.

I have started to play around with killing the Brett with potassium metabisulfite (campden tablets) to stop fermentation before the gravity gets too low, this is a good idea for high gravity beers that would otherwise get too thin. Heat pasteurization and sterile filtration are two other options, but ones I haven’t tried.

I have not risked adding Brett at bottling, both thick bottles and a very low FG would be required to ensure that you did not end up with explosive carbonation, and even then carbonation would be unpredictable.

Temperature?
For primary Brett C fermentations I have gotten good results going very light on the pre-pitch aeration and ramping up the temperature into the high 70s, but Brett A seemed to do better with more oxygen and a lower fermentation temp (~68).

For secondary fermentation I tend to keep the temperature in the mid-low 60s for as high temps seem to encourage more aggressive acid formation and more oxidation over the long aging period.

Wort considerations? Grist?
Just about any grist can play well with Brett. In addition to the base beers I have used (Belgian Strong Dark, Belgian Single, Saison, Imperial Stout, Old Ale, Belgian Blond etc…) On the commercial side I have had a Mild, a Belgian Pale, and a Strong Scotch that were barrel aged with wild yeast and bacteria with delicious results.

I would not go too heavy on the dark malt or other assertive malts as they can become harsh as the beer heads towards its low FG.

Brett and hops play well together, particularly Brett B (for example in Orval, Ommegeddon, and Deification), but bitterness and sourness do not go well so watch the bittering hops if you are adding bacteria. Aroma hops will generally fade before the Brett is really assertive, so a dry hop addition right before bottling is often a good idea.


Mashing schedule?
A higher mash temperature will ensure plenty of residual dextrins for the Brett to eat in secondary, so it’s a good idea to raise it up particularly if you do not have much in the way of cara/crystal malts in your grist. A lower mash and simpler grain bill can be used if you would prefer just a hint of Brett in an otherwise clean beer.

I would go about the rest of my mash in the same way I would for any other beer, based on the malt bill. I generally do single infusion mashes and get good results.

I haven't done enough 100% Brett beers to have much to say about how mashing effects them, but it doesn't seem like the mash temp has as much of an impact on the FG as it does in a Saccharomyces beer.

pH?
Brett is tolerant of a wide pH range. It can produce some acids to lower the pH, but I have tasted only one Brett beer, which did not also have lactic/acetic acid bacteria, that I would call sour. That one beer was a low gravity beer that was fermented with Brett C in the upper 50s, certainly an area for experimentation.
Time (length) of fermentation? Determination of completion.
In the secondary generally a minimum of 6-9 months is needed to reach a stable FG, sometimes it takes longer.

Brett primary fermentations are relatively quick. Generally a stable FG is reached within 2 weeks, fermentation looks normal, and the Brett flocculates reasonably well. I have 100% beers that are 18 months old which still have stable carbonation, so it is certainly a faster way to turn out funky beers.

In both cases having consistent FG measurements over time is the only way to be certain fermentation is completed. Flavor is also a good general indicator as is appearance (when the pellicle drops it is probably safe to bottle).


Attenuation levels?

In 100% Brett beers my attenuation tend to get into the low 80s, in secondary 90%+ is pretty common. Some strains are more aggressive than others and the wort composition will have an effect, but as a general rule most beers with Brett will eventually end up between 1.004 and 1.010.


Flavor development?

For 100% Brett the flavors are pretty steady, although sometimes a beer can go from fruity when young slowly towards the more “classic” leather, barnyard, horse blanket etc… as it ages.

For Brett in the secondary the primary strain is really only important in that it will dictate how much sugar is left over for the Brett (the higher the gravity left the bigger impact the Brett will have). Any esters/phenols from the primary strain will be broken down or covered up by the Brett. The Brett character will continue to get more aggressive as it continues to ferment and then seems to mellow as time passes after fermentation is complete and it ages in the bottle.
Bottling?
I have never had an issue with an over-carbonated Brett beer, but that is probably because I always make sure the fermentation is finished (indicated by steady gravity readings) before bottling.

Many people add an acid/alcohol tolerant strain or Saccharomyces (American ale yeast, or even a wine yeast) at bottling to ensure carbonation, but I have never had an issue when I have failed to re-yeast. Pitching fresh Brettanomyces is also an option that may increase complexity over time.

One pitfall to watch for is the level of dissolved CO2 in the beer at bottling. After a long period of time in secondary, particularly when oak is involved because it provides nucleation sites, the beer can be completely flat. Normal priming sugar calculations assume a certain amount of residual carbonation based on the temperature of the beer, without this carbonation the beer will seem flat even after the yeast consume all the priming sugar. To remedy this you can give the beer a small feeding (2-3 oz) with table/corn sugar a week or so before bottling or additional priming sugar at bottling.


Sanitation Issues?
To be completely safe you would need to have a separate set of equipment for everything after pitching (fermenters, tubing, bottling bucket, bottling wand, stoppers, airlocks etc…). I have separate tubing and bottling wands, but everything else is cleaned with hot water and OxyClean Free and sanitized with cold water and Star-San before and after every use. I have been told 30 seconds is all Star-San needs, but I normally soak things in it for most of brew day to be sure.

Despite all of those funky beers and shared equipment I have had only one “clean” batch go funky. It was a mild that was transferred into a fermenter on the same day I transferred a 100% Brett beer out. It still took several months for the infection to show up, and it was actually pretty tasty to me, but it wasn’t what I was going for.

Other Info?
Oak and Brett play very well together as Brett can eat the wood sugars over a long term secondary fermentation. The oak also provided an easy method to transfer the yeast from one secondary to another, or to save microbes for a future batch by drying the oak and then saving it.

Brett also likes a bit of oxygen as it slowly ferments. There is a large amount of debate over how much is good and how to get it into the beer. Traditionally in a brewery this is done by aging the beer in large wooden barrels, but this isn’t practical for most homebrewers (although I know some who have wine barrels). As a result people have developed a variety of strategies, from sticking an oak peg through the neck of a carboy (Raj Apte), to aging in plastic, to aging in small barrels, to venting the headspace periodically. None of these methods is perfect, but I have been leaning towards aging in Better Bottles recently as they are more permeable that glass, but considerably less so than the standard homebrew buckets.

Experimentation and realistic expectations are two keys to success. There is still so much to learn about brewing with Brett so pushing the boundaries is a necessity. There is no way around an occasional off batch that is just the nature of brewing with wild yeast. Most commercial breweries that use Brett or bacteria blend their beers, this is certainly a fun and interesting way to play with homebrews particularly blending funky and clean beers.

28 comments:

Brad said...

"Any esters/phenols from the primary strain will be broken down or covered up by the Brett."

Mike, I hope you're right about this, as I have my very first Brett beer currently in secondary -- and I would not have inoculated it had the base beer (a Dubbel) not been hit so hard by unpleasant phenols.

The Mad Fermentationist (Mike) said...

I've had Brett reduce/eliminate minor phenolic characters, but I'm not sure how it will deal with a major issue. I'd certainly like to hear how it turns out.

Duncan said...

I am very interested in storing bugs in wood cubes. I have been doing it in jars etc.. for a bit now but always in a wet environment. You are saying above I can let the cubes dry out and they will still be viable?

The Mad Fermentationist (Mike) said...

Yep, I tried it with decent results. Just let the cubes soak for a few weeks to make sure that the microbes get down into the wood, then dry on a rack in a cool/dry place (I’d avoid direct sunlight and really hot temperatures so it is gentler on the microbes). Make sure you get them fully dried before storage or you risk mold growth.

Al (of East Coast Yeast fame) used wood cubes that he drilled holes in to increase the surface area, Vinnie (or Russian River fame) did something similar with oak chips. The advantage is that it freezes the microbe population (you don’t have to worry about one microbe outcompeting the rest) and doesn’t require regular feedings, but I’m not sure how quickly the different strains die off.

Good luck.

Greg Norton said...

Have you bottle conditioned any of your 100% brett beers?

I fermented a blonde with 100% Brett C. In about two weeks it dropped the gravity from 1.055 to 1.010 and seems to be stable there.

I was considering whether I should just prime and bottle like a normal beer, or if I need to add a secondary yeast strain to carb the bottles. Any thoughts?

The Mad Fermentationist (Mike) said...

No need to reyeast, the Brett will do the job without issue. I've bottle conditioned all of my 100% Brett beers, usually takes 2-3 weeks, and I've now had some of them in the bottle for 4 years that have not become over-carbonated. I might give the beer one more week just to be positive that fermentation really is complete. Enjoy!

Brian L said...

Im brewing an all Brett tomorrow and will be pitching only brett-b and pedio. Would you have any concerns with this combo and not using any clean yeast alongside?

The Mad Fermentationist (Mike) said...

That should be fine, the Pedio may make it buttery at first, but the Brett will clean things up. If you want sourness though it won't be any faster than a traditional mixed fermentation with brewer's yeast. Good luck!

Brian L said...

Is there a down-side to using just Brett and Pedio? Upside?
Is it a faster fermentation alongside brewers yeast?

The Mad Fermentationist (Mike) said...

I've never done (or read about) a Pedio/Brett only beer. My only concern is that Brett can wrap up fermentation quickly as the primary fermenter, not sure how it will do cleaning up after Pedio does its thing.

BrianL said...

I hope that's not a bad thing. Thanks a lot for your comments. Your blog is most informative and has been a huge help to me. I look forward to future posts.

Ricky said...

I have a saison that I am going to add brett b. to the secondary. I did a forced ferment test and the test showed a 1.006 F.G. The actual beer should be higher, but I was wondering where the cutoff would be for the brett to funky up the beer. I was also wondering if I should add maltodextrin if it is too low?

The Mad Fermentationist (Mike) said...

Brett doesn't need much gravity to do its thing, it is really the lactic acid bacteria that benefit from a high FG. There are plenty of breweries that pitch Brett at bottling, or swear that bottle conditioning after aging is the key to getting the character they want. You can age the saison with Brett and if the flavor gets close, bottle it and let that take the character where you want it. If you don't taste any Brett you can always feed it.

Unknown said...

I am brewing my first sour now. When you say that a small amount of Brett into the secondary is fine, how much is this small amount for a 4 gallon batch?

The Mad Fermentationist (Mike) said...

~2 billion cells, about what is in one White Labs tube. This is much less than what is in a Wyeast pack. You could also add a few bottles worth of dregs. Fewer cells will work, but it will take longer to get the same amount of attenuation and amount of flavorful byproducts.

gail said...

Hi Michael,

I have a question that keeps returning for me, and you triggered it again here. You say that it is difficult to calculate the carbonation from bottling-time innoculation with brett. Orval and others have done this, and the classic geuze-makers are able to calculate carbonation simply by undertanding the gravity of the older and newer batches they blend. I've been looking for simple plug-in math or a calculator for years, but that hasn't worked. What would the logic be for a formula? In a fermenting beer, a drop of X points of gravity should yield a standard portion of CO2, right? If you had two beers to blend and you had decided on 40/60 as the ratio, with the first beer at 1.001 and the second at 1.009, would it be possible to calculate that the blend would fall to 1.001 and that the CO2 produced was Y units, giving a pressure of Z in your bottles?

When I first thought about this, I dropped it because my various blendable beers all have come from different worts. My process has not be all that repeatable sometimes, and I have wanted to play around with various grains like wild rice and buckwheat in my sour beers anyway. Still, understanding that starting with the same OG and ingredients might be needed, there should be math to get this right.

Any insights or pointers?

Much appreciated -- Gail Williams

Mario Maduro said...

Mike,

I'll be pitching Brettanomyces on the secondary, probably this weekend, but I still have a doubt regarding oxygenation, should I do it or just pitch the correct amount is my only concern?

Thanks in advance.

Greetings from Brasil!!

Mario Maduro

The Mad Fermentationist (Mike) said...

No need to aerate at this point, it'll do more harm than good. Brett does fine without oxygen, it just takes lots of time for it to ferment out completely. This is different than a 100% Brett primary fermentation where the oxygen and simple sugars lead to a much faster fermentation.

elKomenda said...

Hi,
I have a similar issue as Greg Norton. I have fermented my October Strong Ale with London Ale. It dropped from 1.08 to 1.016 in two weeks. Then I've added bretanomyces culture (truly an old ale Wyeast blend). It sits on beer for 5 weeks now. I started thinking about bottling and I'm concerned whether so little bret will do the job of carbonating the beer - I don't believe any sacharomyces are still healthy. By the way, do you think 5-6 weeks of secondary is enough to give the beer some wild character?

The Mad Fermentationist (Mike) said...

The issue isn't that 5-6 weeks might not be enough for character to develop (Brett will keep adding its character in the bottle), it's that the gravity won't be stable yet. If the Brett is still chewing through dextrins, you will end up with a very over-carbonated beer. Wait until gravity readings don't change from one month to the next. Brett should be enough to eat the priming sugar and carbonate the beer, but if you are worried rehydrate a couple grams of wine yeast and pith that at bottling. Good luck!

Michael B said...

How did the metabisulfite work in halting the brettanomyces?

I'm working on a solera-type project atm. My original brett/pedio/lacto beer has been going for about seven months now. My intention is to brew up another batch (which is undergoing a sour mash atm); ferment that out with regular saccharomyces; and then mix the older batch with the younger batch. After mixing I plan on bottling half of the mixture and letting the other half continue to age.

My concern is that the unfermentables (by sacch standards) left in the young batch will wake up the brett and other bugs when I mix the two batches. This is good for the half I want to age but not the half I want to bottle. If I could metabisulfite + Ksorbate the brett into a docile state that would be great. Of course, after knocking the yeast out like that I assume I'd have to re-pitch a small amount of sacch yeast with priming sugar to get carbonation in the bottle.

Pasteurization is something I'd like to avoid since I've been lead to believe that it will notably affect flavors. I'm not too incredibly familiar with using a sterile filtration method but I recall hearing that filtration won't catch certain smaller species of brett/pedio/lacto.

Kegging has also crossed my mind but my fear is that the beer will be consumed too fast and that I'd have to change out my draft line when I went back to a non-bug beer.

Any advice you have would be appreciated.

Cheers.

The Mad Fermentationist (Mike) said...

The technique worked really well. Just gave a "thank you" bottle to Ron Pattinson for his help with the Courage recipe all those years ago. You're spot on that you'd have to reyeast and prime after the sulfite dissipates. Haven't used sorbate in beer, not necessary.

Johnny said...

Do you rack your 100% Brett beers indoors? I'd never considered the risk of airborne Brett becoming a roommate of sorts, but a brewer friend of mine was pretty alarmed to hear that I'd racked to secondary inside the house. Your comment about your mild becoming infected after transferring on the same day as a Brett beer hints at this situation, but it sounds like a very short-term issue.

The Mad Fermentationist (Mike) said...

The issue with the mild was that it was into the same fermentor the 100% Brett beer was in using the same equipment. Brett isn't commonly airborne, although it can be sent into the air by a violent blow-off for example. Personally I don't worry about transferring inside, there are all sorts of microbes already in your house, if your sanitation/process keeps them out, you're already doing things right!

Johnny said...

That was pretty much my thinking as well. Thanks for being such a good resource! I've been consulting your website quite a bit as I dip my toes into brewing with Brett. Looking forward to the book!

Rachael said...

Hello Michael,
I'm enjoying reading over your blog - it is answering questions I've had for awhile on the use of Brett. I was referred to you by an advanced member of the HBD (HomeBrew Digest Forum).
My question is about Brett in Secondary... I've just brewed a 45 gallon batch of Orval (my first time). It is happily chugging away in primary, and I am currently building up a starter for the Brett that will be pitched in to secondary. How large of a starter would you recommend? I started with Wyeast 5112 (smackpack-like package) and pitched it in to 1/2 gallon of wort. I'm ready to step it up, was going to shoot for between 2-3 gallons to pitch in to the Orval secondary. Is this about right for the amount of Brett to add?

In addition, I'm going to build up the Brett an extra 1/2 gallon to what I need for the Orval and use for secondary in one of my hoppy APA's (after reading your blog and how you add Brett to your extremely hoppy IPA's, I'm feeling quite creative!) How long would you leave Brett in secondary like this? The current FG on the APA is 1.012. Thanks in advance for your input.

The Mad Fermentationist (Mike) said...

The 1/2 gallon starter is probably plenty. Those Wyeast Brett packs actually have quite a few cells, just a bit less than the standard 100 billion cell brewer's yeast packs. Even pitching straight you'd be at 500,000 cells/mL, which is more than many breweries pitch for secondary fermentation.

Cheers and best of luck!

Rachael said...

Hi Mike,
Thank you for the information - this is good to know about the amount of yeast cells in the Brett packs.
You won't believe this, but it's been 7 days since I pitched the 1/2 gallon, so tonight - BEFORE I saw your response - I pitched 3 more gallons of wort in the starter. Now I'm a little concerned - should I only pitch a half gallon of it? I don't want this Orval to be overpitched on the Brett. As you can understand, with 45 gallons I want it to be perfect. I really have no interest in experimenting with this particular brew.

Thank you in advance - I'm interested to hear your thoughts. (And I swear I won't take anymore action until I hear from you).

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