Brettanomyces is a non-spore forming genus of yeast in the family Saccharomycetaceae, and is often colloquially referred to as "Brett". The genus name Dekkera is used interchangeably with Brettanomyces, as it describes the teleomorph or spore forming form of the yeast, but is considered deprecated under the one fungus, one name change. The cellular morphology of the yeast can vary from ovoid to long "sausage" shaped cells. The yeast is acidogenic, and when grown on glucose rich media under aerobic conditions, produces large amounts of acetic acid. Brettanomyces is important to both the brewing and wine industries due to the sensory compounds it produces.
In the wild, Brettanomyces lives on the skins of fruit.
In 1889, Seyffert of the Kalinkin Brewery in St. Petersburg was the first to isolate a "Torula" from English beer which produced the typical "English" taste in lager beer, and in 1899 JW Tullo at Guinness described two types of "secondary yeast" in Irish stout. However N. Hjelte Claussen at the Carlsberg brewery was the first to publish a description in 1904, following a 1903 patent (UK patent GB190328184) that was the first patented microorganism in history. The term Brettanomyces comes from the Greek for "British fungus".
Yeast in winemaking
When Brettanomyces grows in wine it produces several compounds that can alter the palate and bouquet. At low levels some winemakers agree that the presence of these compounds has a positive effect 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 Château Musar. However, when the levels of the sensory compounds greatly exceed the sensory threshold, their perception is almost always negative. The sensory threshold can differ between individuals, and some find the compounds more unattractive than others. While it can be desirable at lower levels, there is no guarantee that high levels will not be produced.
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Lambic (lɒ̃bik,_'læmbɪk) is a type of beer brewed in the Pajottenland region of Belgium southwest of Brussels and in Brussels itself since the 13th century. Types of lambic beers include gueuze, kriek lambic, and framboise. Lambic differs from most other beers in that it is fermented through exposure to wild yeasts and bacteria native to the Zenne valley, as opposed to exposure to carefully cultivated strains of brewer's yeast. This process gives the beer its distinctive flavour: dry, vinous, and cidery, often with a tart aftertaste.
The role of yeast in winemaking is the most important element that distinguishes wine from fruit juice. In the absence of oxygen, yeast converts the sugars of the fruit into alcohol and carbon dioxide through the process of fermentation. The more sugars in the grapes, the higher the potential alcohol level of the wine if the yeast are allowed to carry out fermentation to dryness. Sometimes winemakers will stop fermentation early in order to leave some residual sugars and sweetness in the wine such as with dessert wines.
The process of fermentation in winemaking turns grape juice into an alcoholic beverage. During fermentation, yeasts transform sugars present in the juice into ethanol and carbon dioxide (as a by-product). In winemaking, the temperature and speed of fermentation are important considerations as well as the levels of oxygen present in the must at the start of the fermentation. The risk of stuck fermentation and the development of several wine faults can also occur during this stage, which can last anywhere from 5 to 14 days for primary fermentation and potentially another 5 to 10 days for a secondary fermentation.
Delves into the science of food fermentation, covering lactose metabolism, soy food fermentation, human milk production, kimchi making, and bacteria isolation.
Fundamental aspects of chemostat cultures are reviewed. Using yeast cultures as examples, it is shown that steady states in chemostats may be predicted quant. by combining the correct no. of unstructured kinetic models with expressions for existing stoichi ...