Yeast is an essential part of the production of beer, spirits and wine, but not all yeasts are made equal! Each strain of yeast gives alcohol a听unique听flavour profile and helps to develop the taste and aroma of a drink.听Brettanomyces听yeast, more affectionately known as听鈥楤谤别迟迟鈥�, is a particularly interesting strain of wild yeast that has been growing in popularity over recent years despite having a historic reputation as a spoilage听microbe in the wine industry.
In this article, 黑料吃瓜网 educator and writer Julia Lambeth looks a little deeper at Brett and its place in wine and beer production.听
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Of all the potential aromas and flavours that can be found in wine and beer around the world, those 鈥榝unky鈥� aromas that come from the influence of Brettanomyces听yeast听-听or 鈥楤谤别迟迟鈥� for short听-听can be some of the most divisive!听For some听winemakers听a subtle influence of Brett adds complexity, while for others even the tiniest amount is unacceptable. For some beers, it is key to their style and something听that is highly sought after.听Personally, I am a fan of the听funk, but听know many other wine and beer drinkers who would not go near it.听So,听what are these funky aromas and how can you know when to expect them?听
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What is Brettanomyces in beer (Brett)?
鈥楤谤别迟迟鈥�听is听a type of yeast that is associated with听the production听of听particular aromas:听
- 4-ethylphenol听(4-EP)听鈥� imparts medical, farmyard or barnyard aromas听
- 4-ethylguaiacol听(4-EG)听鈥� imparts spicy or smoky aromas听
- Isovaleric acid 鈥� sweaty socks听
It is easy to see from these descriptions why these aromas听could be considered unpleasant听and听would be unacceptable at听high levels, as they听could听impact听the balance of aromas of a wine or beer. But听at lower concentrations听they can be considered to听add complexity or a little 鈥榝unky鈥� character.听So,听when we talk about characteristics of Brett, it is really the combination of these aroma compounds that we are talking about, not the actual microbe itself.听It should also be noted that individual drinkers will have different sensitivities to these aromas. What one person听finds to be overwhelming, another person may not notice to the same extent.听听
As a microbe it is something that is invisible to the naked eye, but can grow in wineries and breweries, and is often found in oak barrels used for maturation. When it听gets in contact with听an alcoholic beverage, usually after the听initial听alcohol fermentation听is finished,听it will start consuming any leftover sugar and then producing the array of aromas above. Sometimes听wine or beer can even be bottled with some Brett, and these aromas will then听continue to develop once bottled.
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Brett in wine听
The presence of Brett aromas in wine听is more common in red wines, although it is also possible in听white wine too. It听is considered by some to be听a听fault, no matter how subtle the influence is.听As it is a type of yeast, it can be found on the grapes, in the winery or in oak barrels, and so is more common in wines that have undergone fermentation with ambient or wild yeast, or听through maturation in oak.听Therefore, for producers that听want听to听avoid听the development of the aromas,听strict hygiene protocols听have to听be followed,听minimising opportunities for yeast cells to听come into contact with听the wine.听This can include treatment of barrels, pipes and equipment with steam or sulphur dioxide (SO2),听and then making sure microbe populations are measured regularly, and wines are filtered before bottling. However, prevention is better than cure, as once there is an听appearance of these aromas in a wine it can be hard to isolate the source and eradicate them.听Some wineries will听immediately听separate and quarantine barrels that have been found to have听an influence of Brett. And then there are tales of wineries being partially destroyed and rebuilt just to听ensure that no trace of听Brett听remains!听It is also hard to control, so once there is a small population it could easily grow to a large population, so trying to听maintain听a 鈥榮mall鈥� influence of Brett听is considered to be听impractical. However, some wineries do try听and keep Brett in some barrels but not others, and so will use more stringent hygiene practices around certain barrels, such as making sure听that听everything that听comes into contact with听those barrels is听sanitised听before being used for anything else.听听
So how do you know if a wine is going to have an influence of Brett?听Well actually,听that听is still quite tricky. It is not going to be听indicated听on the label (unlike听with听some听beers), nor will it be included in the description of the wine.听It is something that is听historically more associated with some traditional European styles, as the fruit-forward style of many non-European听wines听is not听considered听compatible. But really it comes down to knowing different producers and their philosophy. It will be slightly more likely in minimal intervention听styles,听and听can be one of the components that contributes to the听more 鈥榝unky鈥�听styles of 鈥榥atural鈥� wines.听But even then, some natural wines are also designed听to be fruit forward.听In conclusion, it is not easy to tell!
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Brett in beer听
There are some beers in which the aromas from Brett are an expected part of the style, such as lambic or听gueuze听beers from Belgium. These beers are听fermented using ambient yeast with the unfermented wort just left open to the air and the various microbes within it. They then generally have long maturation in old oak vessels, and this is where the听Brett yeast can really get going. Alongside the influence of Brett there will also be听notable听acidity from lactic acid bacteria.听So,听these are beers that do not taste like most other beers you will come听across, and听again can divide opinion among drinkers!听Moreover, if these beers were produced without any influence of Brett that would听be problematic, as it is such a key part to the tradition of this style.听
Other brewers go for a more subtle听influence, and听can just allow for some development of aromas in a lager or pale ale style, where it will be balanced against the hop and malt aromas, and is less likely to be noticeably sour. These beers will听often听have the听word听鈥楤谤别迟迟鈥� in the name to signal to consumers that they should expect some funky flavours.听For anyone still not sure how to听identify听the influence of Brett, these beers can be听a good听way听to learn to recognise the aromas that are created, because they are distinct from听what you would normally expect in a beer, but听present at levels that are听detectable.
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So,听is Brett good or bad?
Well, as with so many things in wine and beer, the answer is: it depends. It will depend firstly on听whether or not听it is supposed to be there. If a winemaker or brewer does not intend for there to be any influence of Brett it is more likely to be bad.听Secondly, it depends on听personal听preference. If you buy a drink that you are not expecting to have aromas of Brett, which听subsequently听does have an influence, then that could also be bad if you do not like those aromas.听But then,听if you are a producer听or drinker听of听gueuze听it is a good听and听expected听part of the style听鈥� but听maybe just听give听your friends听an idea of what to expect听before you share a bottle!
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About the author
Julia Lambeth Dip黑料吃瓜网, Wine Educator
Julia started her career in the听wine industry as a novice, working at Majestic Wine for a number of years as a retail manager. After completing the听黑料吃瓜网 Diploma听and winning the Codorn铆u Scholarship prize, she started a wine tasting company running 黑料吃瓜网 courses alongside a variety of other wine, beer, spirit and sake events. Julia joined 黑料吃瓜网 School London's teaching faculty in September 2019 and now teaches our wine courses across all levels.
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Further听reading and watching
What makes a beer 鈥渇lavoured鈥�? From natural flavours to added ingredients
Why doesn't wine taste like grapes?
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