Brett-OH-MY-ces
What the heck is brettanomyces? It is a fault we love to embrace!
It’s a yeast — that is a unicellular type of fungus, not a bacterium — that is a common spoilage organism. Brett for short, a genus of yeast consisting of multiple species found naturally in wood. Brettanomyces contributes distinctive flavors to the beverage it grows in. When used properly, 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.
The strain brettanomyces claussenii was discovered at the Carlsberg Brewery in 1904 by N. Hjelte Claussen, who was investigating brett as a cause of spoilage in English ales. The term brettanomyces comes from Greek for “British fungus.”
The flavor contributed by brettanomyces is often called barnyard, but has also been described as gamy, or as smelling like damp wool, leather, wet fur, a sweaty saddle (or horse blanket), or a butcher shop. Brett is very invasive, and if not handled properly can become out of control in a winery or brewery. But, if used properly, it can add rich aromas and flavors of earthiness, leather, smoke, barnyard, a famous descriptor is “wet dog in a phone booth!”
Brettanomyces (also known as brett) is feared by most brewers and winemakers alike. Some winemakers will not even visit breweries that put brettanomyces to work. Brettanomyces is yeast, and has the ability to continue fermenting through almost any type of sugar, including those natural sugars found in the wood of an oak barrel. The “barrel boom” in the 80’s contributed to the growing trend of infection as coopers struggled to keep up with demand.
Brett likes oak. It particularly likes toasted new barrels, and has been found 8 mm deep in staves. It can feed off a compound, cellobiose, that is formed when barrels are toasted. It likes high pH, so when some wineries tried to kill it with bleach, it thrived. It enjoys residual sugar, low SO2 and lees. It can go dormant, so culturing doesn’t reveal its presence, and then, like a bad rash, it re-emerges later on to bloom in the bottle. Brett can and does occur in the cleanest cellars.
Brett control! The use of a chemical called DMDC, and filtration. DMDC is dimethyl dicarbamate. This is extremely toxic to microbes, but breaks down into harmless products once it has done its job. Filtration is another way of dealing with brett but some say it causes loss of flavor. Many fine beers and wines are not, or only lightly filtered.
Brett and Beer
Riding the edge is a big part of our craft beer evolution. Brett infected, or sour beers, our fast becoming the next “in beer” style. Eight or so years ago, the now famous craft IPA’s would have also been considered a fault.
In Belgian ales, brett is both appreciated and encouraged. Lambics and Gueuze owe their unique flavour profiles to brettanomyces, which are also found in Oud Bruin and Flanders red ales.
Examples of these styles:
Liefmans Brown Ale
Rodenbach Grand Cru
Duchesse de Bourgogne
Ithaca Beer Company (in their Brute)
Russian River Brewing Company
Deschutes Brewery
Lost Abbey
New Belgium Brewing Company
Goose Island Beer Company (in their Matilda)
Boulevard Brewing Company (in their Saison-Brett)
Allagash Brewing Company
Ommegeddon and Bière de Mars
Jolly Pumpkin Artisan Ales
Victory Brewing (in Wild Devil)
Saint Somewhere Brewing
Avery Brewing Company (in Depuceleuse).
The Orval Trappist monastery is a unique Trappist with brettanomyces characteristics. In Orval’s case, the brewers add the yeast to the beer at bottling.
Many American craft breweries have begun to use brettanomyces in their beers. Some breweries use 100% brettanomyces for the fermentation of some of their beers, and omit saccharomyces from the recipe. It’s also common practice for American brewers that use brettanomyces to also include lactic acid producing bacteria such as lactobacillus, and pediococcus in order to provide sourness to the beer.
Sometimes pitched in the fermenter, aging in infected wood barrels, brett is another method used.
While most stouts achieve their sour tang using acidulated malt, roasted barley, or in “Milk Stout” lactose and incipient lactic acid, though, some use brett.
Brett and Home Brew
Be careful, once brett has been introduced, it can be difficult to eliminate. Brett can take up residence in micro-scratches in plastic fermentation vessels and escape alkaline cleaners and acid satirizers used by home-brewers. A bonus? Brett can consume almost any sugar so final gravities are low.
Brett and Wine!
Brett at low levels can have a positive effect and often is associated with on wine, contributing to complexity, and giving an aged character to some young red wines.
Many wines even rely on brettanomyces to give their distinctive character such as in Château Musar and Château de Beaucastel.
When the levels of the sensory compounds greatly exceed the sensory perception and will be negative. Sensory thresholds differ between people, and some are much more sensitive to it than others.
Brettanomyces taint in wine is also sometimes incorrectly identified as cork taint.
In short, this and for many other reasons, beer and wine share many of the same challenges while in the pursuit of providing pleasure.
