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 OxiClean 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.