| Brettanomyces bruxellensis | |
|---|---|
 | |
| Appearance of colonies ofBrettanomyces bruxellensis on YPD (Yeast Peptone D-glucose) agar. | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Saccharomycetes |
| Order: | Saccharomycetales |
| Family: | Pichiaceae |
| Genus: | Brettanomyces |
| Species: | B. bruxellensis |
| Binomial name | |
| Brettanomyces bruxellensis Kufferath and von Laer | |
Brettanomyces bruxellensis (theanamorph ofDekkera bruxellensis) is ayeast associated with theSenne valley nearBrussels,Belgium. Despite its Latin species name,B. bruxellensis is found all over the globe. In the wild, it is often found on the skins of fruit.
B. bruxellensis plays a key role in the production of the typical Belgianbeer styles such aslambic,Flanders red ales,gueuze andkriek, and is part of spontaneousfermentation biota. The Trappist Orval has very little in it as well. It is naturally found in the brewery environment living within oak barrels that are used for the storage of beer during the secondary conditioning stage. Here it completes the long slow fermentation or super-attenuation of beer, often in symbiosis withPediococcus sp. Macroscopically visible colonies look whitish and show a dome-shaped aspect, depending on the age and size.[1]
B. bruxellensis is increasingly being used by American craft brewers, especially in Maine, California and Colorado.Jolly Pumpkin Artisan Ales,Allagash Brewing Company, Port Brewing Company,Sierra Nevada Brewing Company,Russian River Brewing Company andNew Belgium Brewing Company have all brewed beers fermented withB. bruxellensis. The beers have a slightly sour, earthy character. Some have described them as having a "barnyard" or "wet horse blanket" flavor.[2]
In thewine industry,B. bruxellensis is generally considered a spoilage yeast and it and other members of the genus are often referred to asBrettanomyces ("brett"). Its metabolic products can impart "sweaty saddle leather", "barnyard", "burnt plastic" or "band-aid" aromas to wine. Somewinemakers inFrance, and occasionally elsewhere, consider it a desirable addition to wine, e.g., inChâteau de Beaucastel, butNew Worldvintners generally consider it a defect. Some authorities considerbrett to be responsible for 90% of the spoilage problems in premium red wines.[citation needed]
One defense againstbrett is to limit potential sources of contamination. It occurs more commonly in somevineyards than others, so producers can avoid purchasing grapes from such sources. Usedwine barrels purchased from other vintners are another common source. Some producers sanitize used barrels withozone. Others steam or soak them for many hours in very hot water, or wash them with eithercitric acid or peroxycarbonate.[citation needed]
If wine becomes contaminated bybrett, some vintners sterile filter it, addSO2, or treat it withdimethyl dicarbonate. Both knowledge and experience are considered helpful in avoidingbrett and the problems it can cause.[citation needed]
B. bruxellensis contains the enzymevinylphenol reductase.
