What is Brett or Brettanomyces?

To fully understand the nature of Brett, I would like to start with the illustrative comparison made by the English writer Michael Jackson: “Saccharomyces is like a dog and Brett is like a cat. It’s a little less predictable. It’s going to do its own thing; it’s not going to come when you call it and sit when you say sit. If you can respect its individuality and suggest rather than dictate what it does in your fermentation, it can reward the brewer and the drinker."

If we take a look at the history books, we learn that this type of yeast was discovered in 1904 by N. Hjelte Claussen, director of the laboratory of the New Calsberg brewery, and was identified as the agent that causes the characteristic flavor of traditional English ales (from the 17th century and earlier). Brettanomyces, in Greek, means "British Fungus" (source: milkthefunk.com).

Despite the desirable qualities that Claussen saw in Brett, the reality is that since in the late 19th century when cultivations of Saccharomyces cerevisiae and Saccharomyces pastorianus began to be adopted in the beer and wine industries, Brettanomyces has been historically perceived by brewers - with an exception to those who brew Lambic or Flanders Red / Brown - as an organism that spoils beer. This due to phenols, acids and cloudiness that it sometimes produces in beers.

However, in recent years, some pleasant flavor and aroma components have been identified in beers with Brettanomyces. For example tropical notes of pineapple, stone fruits or, to a certain degree, the acetic acid. This circumstance has led to a notable increase in its popularity among brewers outside Belgium and also the consumers.

Talking with Marc Baulida, Brewer at La Calavera

To get a little closer to Brett yeasts, we have thought that what better than asking who in my opinion is an epitome in the brewing process of sour and / or wild beers in Spain. I'm referring to Marc Baulida, Brewer at La Calavera.

La Calavera (Sant Joan de les Abadesses, Girona) was born as a homebrewing project started by Marc himself together with Mikel Mendizabal, in 2012. They started selling their beers at La Barricona restaurant (Ripoll), and after positive recognition from the consumers, they decided to professionalize their brewing.

Although in the beginning the beers they brewed were of ale-type fermentation and more classic (styles of beers that they still continue to brew to this day), the truth is that today their identity in the craft scene is more marked by their more risky and experimental beers. As Marc himself acknowledges: “the specialization in barrel-aged beers, whether in dark styles or wild / sour styles, gives us a dynamic of constant research and learning. More and more, our beers stand out for their maturation, aging and the passage of time”.

If you like sour beers, with mixed / spontaneous fermentation and / or barrel-aged, you only have two options: either you love La Calavera beers, or you haven't tried them yet. There is no middle ground.

To all beer geeks and aficionados who read this, I would like you to keep this in mind next time you go beer shopping: La Calavera is one of the brewers that participated in the last edition of The Festival (Buffalo, New York, 2019), an event hosted by the Shelton Brothers. A microbrewery in a town in Girona, very local, popular, and who lives away from the spotlight, rubbing shoulders with the best of the best internationally, with familiar names like Fonta Flora, Jester King, Trillium, Cantillon or 3 Fonteinen, among others. And we have Calavera right here, close to us them!

The quality of their beers is not something that has gone unnoticed, and the proof for this is that they can be found in countries such as France, Italy, Switzerland, Netherlands, Belgium, Russia, England, Finland, United States, China, and Sweden. This is why I recommend that you check out their “Wood Series” (Dark and Sour) barrel beers portfolio, and you will find authentic gems.

But let's go back to the topic of the article, and to the questions we have asked Marc to shed some light on the exciting, complex and wonderful world of beers with Brett. Thank you very much Marc!

Ø: What is "Brett" and what does it do to beer?

Marc: Brett is a type of yeast that acts on beer by acidifying it, that is, transforming the sugar chains into acetic acids, makes it more complex and gives it tropical touches. It depend a lot on the strain, that is, if it is claussenii, lambicus or bruxellensis (since each one has a different profile), and it can contribute to farmyard aromas, goatskin, funky, fruity, pineapple notes, hints of rust, etc. The temperature and the type of sugars found during fermentation also have a great influence.

Ø: How is the production and fermentation process of a mixed fermentation beer different from that of a spontaneously fermented beer?

Marc: The difference is that mixed fermentation is a process in which we first ferment the beer with an Ale yeast, or a Lager yeast, marking an initial beer profile without wild yeasts, and just when it is about to finish we stop the fermentation, and that's when we add a wild yeast. Normally, wild yeasts, whether in barrels or inoculated by means of reproduction, tend to eat the dextrose (sugars) that an Ale yeast does not assimilate, and in this way, it usually transforms that beer that initially had a very "classic" or clean Ale profile, to a different beer.

The spontaneous process, however, consists in that after boiling the beer, instead of cooling it and adding some type of controlled yeast (Ale or even Brett) to the must, nothing is inoculated but is maintained so that it loses temperature little by little, and it is inoculated with the yeasts or bacteria that are in the environment. We could say that the beer is left to contaminate itself with all the microorganisms that float in the air.

Normally, spontaneous fermentation usually ends in some type of barrel so that after that wild or ambient inoculation, the barrel will finish the job, of rounding it out. It is a very long process and takes a long time, since there can be many types of bacteria in the mix and some take more time in order for the result to be something positive.

Ø: The use of Brett is usually combined with lactic acid bacteria such as Lactobacillus and Pediococcus. Could you explain, briefly, what role each of these three plays in the fermentation “party”, and what they contribute to the final result - aromas, flavors, textures, character, etc. - in a beer?

Marc: When there is a barrel fermentation or a mixed fermentation process, which is what we do, normally many types of microorganisms, bacteria or wild yeast are inside the barrels. In our case, many times we help the Brettanomyces with other Brett blends that make the fermentation have more nuances, and sometimes we also start with a kettle sour base or a beer brewed with lactic acid.

Lactic acid gives a fairly established sour flavor base, and over time, this flavor also matures. It is a bacteria that ages well and adopts other types of complexities, aromas and profiles.

I have the least experience with Pediococcus, but we could say that above all it initially provides a very beastly texture (like mucus), and then those defects (texture, bad flavors, etc.) are transformed by Brett into acetic components and organoleptic notes that give very clean nuances and fit very well with acid profiles.

Ø: What type of malts, or what combinations of them, are in your opinion the most recommended to enhance the work of wild yeasts? And when it comes to the selection of hops, do you have any preferences?

Marc: If we talk about types of malts suitable for making sour beers, it will depend a bit on the process, but we can say that Brett yeasts like complex dextrins that ale yeast often fails to assimilate, and they end up transforming them. They are also very fond of a cereal base, even without malting: raw wheat flake, oats, rye. The initial harshness of this type of cereal, over time, is also transformed by the Brett.

For example, we can use Vienna or Pale as a base, but apart from roasted malts, sour fermentations tend to accept everything that are sweet malts and that add complexity quite well.

As for hops, it will depend on the profile that we want to give to the beer, but if we talk about sour beers, hops tend to be second or even third. What we want to highlight in this type of beers is a slightly bitter profile, that there is no competition with the sour or the barrel or yeast notes, and what we seek is to give prominence to the sourness. This is why hops don't have to be very expansive. I personally like to use noble hops, European, more herbal than citrus types (they can also be used, but I'm not a big fan).

Ø: Regarding the addition of fruits, can you tell us when is the best time (or times) to add them, and what aspects are important to take into account at the level of interaction of sugar or other components with the Brett?

Marc: In our case, when we use fruit inside the barrel, we usually add it when the beer is be three or four months away from completion. We give the beer time to absorb the sugars that we are adding to it again, so that it can slowly ferment again and soak up those nuances typical of the fruit.

In the case of making a sour in stainless steel, in the fermenter, we have to add it just at the moment in which the primary fermentation ends, and thus, give the yeast time so that it can eat the sugars in the fruit. Otherwise, we may have some scares and / or gassing problems.

Ø: What benefits does barrel aging bring to beers made with Brett?

Marc: The benefits are mainly at the level of complexity, because by giving the beer such a long break, without temperature changes and a lot of rest, little by little it stabilizes and acquires new flavors. We can say that, in some way, the beer is finding its place.

This complexity is due to a large extent to the fact that the beer is saturated with the flavors of the wood, the fruit, it gains acidity and it becomes clean. The passage of time polishes these possible initial defects and the flavors, aromas and nuances are perfected. The barrel fixes them.

Ø: Finally, of all the beers with Brett that you have made to date, which of them do you think you have nailed?

Marc: After the trajectory that we are taking, in which we are constantly brewing new beers because of the market demand and our experimental line, perhaps the ones that I see more complexity in are GODLESS or SEDITION, two profiles of beers that, within from the world of sours, have a very specific personality and a very marked profile. They have really convinced me and I consider them different from most of the ones we do.