Brettanomyces bruxellensis (the anamorph of Dekkera bruxellensis) is a yeast

Yeast

Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...

 native to the Senne

Senné

Senné is a village and municipality in the Veľký Krtíš District of the Banská Bystrica Region of southern Slovakia.-External links:*http://www.statistics.sk/mosmis/eng/run.html...

 valley near Brussels

Brussels

Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

, Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

. It is one of several members of the genus, which was discovered at the Carlsberg brewery in 1904 by N. Hjelte Claussen, who was investigating it as a cause of spoilage in English ales, hence the name. In the wild, it lives on the skins of fruit.

Beer production

Brettanomyces bruxellensis plays a key role in the spontaneous fermentation of typical Belgian beer

Beer

Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...

 styles such as Lambic

Lambic

Lambic is a very distinctive type of beer brewed only in the Pajottenland region of Belgium and in Brussels itself at the Cantillon Brewery and museum...

, Flanders red ale

Flanders red ale

Flanders red ale is a style of sour ale usually brewed in Belgium. Although sharing a common ancestor with English porters of the 17th century, the Flanders red ale has evolved along a different track: the beer is often fermented with organisms other than Saccharomyces cerevisiae, especially...

s, Gueuze

Gueuze

Gueuze is a type of lambic, a Belgian beer. It is made by blending young and old lambics into a new beer, which is then bottled for a second fermentation. Because the young lambic is not fully fermented, it contains fermentable sugars, which allow the second fermentation to occur...

, and Kriek

Kriek

Kriek is a style of Belgian beer, made by fermenting lambic with sour Morello cherries. The name is derived from the Dutch word for this type of cherry . Traditionally "Schaarbeekse krieken" from the area around Brussels are used...

. It competes with brewer's yeast, as well as other microorganisms, in fermenting the wort, and gives the beer a distinctive taste, which is a desired part of the style.

Wine production

In the wine

Wine

Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...

 industry, Brettanomyces bruxellensis is generally considered a spoilage yeast and is often referred to as brett. Its metabolic products can impart "sweaty saddle leather", "barnyard", "burnt plastic" or "band-aid" aromas to wine. Some winemaker

Winemaker

A winemaker or vintner is a person engaged in winemaking. They are generally employed by wineries or wine companies, where their work includes:*Cooperating with viticulturists...

s in France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, and occasionally elsewhere, consider it a desirable addition to wine, e.g., in Château de Beaucastel

Château de Beaucastel

Château de Beaucastel is a winery located in the southern part of the Rhône valley in France, which is primarily noted for its Châteauneuf du Pape wines produced in a long-lived style. For its red Châteauneuf du Pape, Beaucastel includes all 13 grape varieties that are traditionally part of the...

, but New World

New World wine

New World wines are those wines produced outside the traditional wine-growing areas of Europe, in particular from Argentina, Australia, Canada, Chile, New Zealand, South Africa and the United States.-Early wines in the Americas:...

 vintner

Vintner

A vintner is a wine merchant. You pronounce it like this In some modern use, in particular in American English, the term is alsoused as a synonym for winemaker....

s generally consider it a defect. Some authorities consider brett to be responsible for 90% of the spoilage problems in premium red wines.

One defense against brett is to limit potential sources of contamination. It occurs more commonly in some vineyard

Vineyard

A vineyard is a plantation of grape-bearing vines, grown mainly for winemaking, but also raisins, table grapes and non-alcoholic grape juice...

s than others, so producers can avoid purchasing grapes from such sources. Used wine barrel

Wine barrel

The use of oak plays a significant role in winemaking and can have a profound effect on the resulting wine, affecting the color, flavor, tannin profile and texture of the wine. Oak can come into contact with wine in the form of a barrel during the fermentation or aging periods...

s purchased from other vintners are another common source. Some producers sanitize used barrels with ozone

Ozone

Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

. Others steam or soak them for many hours in very hot water, or wash them with either citric acid

Citric acid

Citric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks...

 or peroxycarbonate.

If wine becomes contaminated by brett, some vintners sterile filter it, add SO2

Sulfur dioxide

Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

, or treat it with dimethyl dicarbonate

Dimethyl dicarbonate

Dimethyl dicarbonate or DMDC is a colourless liquid with a sharp odour. Its primary use is as a beverage preservative and or processing aid or sterilant , and acts by inhibiting the enzymes acetate kinase and L-glutamic acid decarboxylase...

. Both knowledge and experience are considered helpful in avoiding brett and the problems it can cause.