Oenococcus oeni
Encyclopedia
Oenococcus oeni is a Gram-positive bacteria species in the genus of Oenococcus
. It used to be the only species in the genus (which was known as Leuconostoc oeni until 1995). In 2006, the species Oenococcus kitaharae was identified. As its name implies, Oenococcus oeni holds major importance in the field of oenology
, where it is the primary bacteria involved in completing the malolactic fermentation
.
Diacetyl
in wine is produced by lactic acid bacteria
, mainly O. oeni. In low levels it can impart positive nutty or caramel characters, however at levels above 5 mg/L it creates an intense buttery or butterscotch
flavour, where it is perceived as a flaw. The sensory threshold for the compound can vary depending on the levels of certain wine components, such as sulfur dioxide. It can be produced as a metabolite of citric acid
when all of the malic acid
has been consumed. Diacetyl rarely taints wine to levels where it becomes undrinkable.
Oenococcus
Oenococcus is a genus of Gram-positive bacteria, placed within the family of Leuconostocaceae. The only species in the genus used to be Oenococcus oeni . In 2006, the species Oenococcus kitaharae was identified...
. It used to be the only species in the genus (which was known as Leuconostoc oeni until 1995). In 2006, the species Oenococcus kitaharae was identified. As its name implies, Oenococcus oeni holds major importance in the field of oenology
Oenology
Oenology,[p] œnology , or enology is the science and study of all aspects of wine and winemaking except vine-growing and grape-harvesting, which is a subfield called viticulture. “Viticulture & oenology” is a common designation for training programmes and research centres that include both the...
, where it is the primary bacteria involved in completing the malolactic fermentation
Malolactic fermentation
Malolactic fermentation is a process in winemaking where tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation tends to create a rounder, fuller mouthfeel. It has been said that malic acid tastes of green apples...
.
Diacetyl
Diacetyl
Diacetyl is a natural byproduct of fermentation. It is a vicinal diketone with the molecular formula C4H6O2...
in wine is produced by lactic acid bacteria
Lactic acid bacteria
The lactic acid bacteria comprise a clade of Gram-positive, low-GC, acid-tolerant, generally non-sporulating, non-respiring rod or cocci that are associated by their common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and lactic products, produce...
, mainly O. oeni. In low levels it can impart positive nutty or caramel characters, however at levels above 5 mg/L it creates an intense buttery or butterscotch
Butterscotch
Butterscotch is a type of confectionery whose primary ingredients are brown sugar and butter, although other ingredients such as corn syrup, cream, vanilla, and salt are part of some recipes...
flavour, where it is perceived as a flaw. The sensory threshold for the compound can vary depending on the levels of certain wine components, such as sulfur dioxide. It can be produced as a metabolite of 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...
when all of the malic acid
Malic acid
Malic acid is an organic compound with the formula HO2CCH2CHOHCO2H. It is a dicarboxylic acid which is made by all living organisms, contributes to the pleasantly sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms , though only the L-isomer exists...
has been consumed. Diacetyl rarely taints wine to levels where it becomes undrinkable.