Flor: Difference between revisions
Created page with "'''Flor''' is a film-forming layer of specialised yeast that develops on the surface of certain fortified wines during biological ageing, most notably within the Jerez-Xérès-Sherry region of southern Spain. It plays a defining role in the production of styles such as Fino and Manzanilla, shaping both their chemical composition and sensory profile.<ref>Robinson (ed.), ''The Oxford Companion to Wine'', Oxford University Press, 2015, ISBN 97801..." |
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'''Flor''' is a film-forming layer of specialised [[yeast]] that develops on the surface of certain [[fortified wines]] during [[biological ageing]], most notably within the [[Jerez-Xérès-Sherry]] region of southern [[Spain]]. It plays a defining role in the production of styles such as [[Fino]] and [[Manzanilla]], shaping both their chemical composition and sensory profile.<ref>Robinson | '''Flor''' is a film-forming layer of specialised [[yeast]] that develops on the surface of certain [[fortified wines]] during [[biological ageing]], most notably within the [[Jerez-Xérès-Sherry]] region of southern [[Spain]]. It plays a defining role in the production of styles such as [[Fino]] and [[Manzanilla]], shaping both their chemical composition and sensory profile.<ref>Jancis Robinson, ''Oxford Companion to Wine'', Oxford University Press, 17 Sept. 2015. ISBN 9780198705383.</ref> | ||
Flor protects wine from excessive [[oxidative ageing]] while simultaneously driving distinctive biochemical transformations that differentiate biologically aged wines from purely oxidative styles such as [[Oloroso]].<ref>Jackson, ''Wine Science'' | [[Flor]] protects wine from excessive [[oxidative ageing]] while simultaneously driving distinctive biochemical transformations that differentiate biologically aged wines from purely oxidative styles such as [[Oloroso]].<ref>PhD Jackson, Ronald S., ''Wine Science: Principles and Applications'', Academic Press Inc, 14 April 2020. ISBN 9780128161180.</ref> | ||
== Microbiological nature == | == Microbiological nature == | ||
Flor consists primarily of strains of ''[[Saccharomyces cerevisiae]]'' adapted to survive in fortified wines with elevated alcohol levels, typically around 15–15.5% abv. These yeasts form a floating biofilm sustained by oxygen at the wine–air interface.<ref>Ribéreau-Gayon et al., ''Handbook of Enology, Volume 2'', Wiley, 2006, ISBN 9780470010396.</ref> | Flor consists primarily of strains of ''[[Saccharomyces cerevisiae]]'' adapted to survive in fortified wines with elevated alcohol levels, typically around 15–15.5% abv. These yeasts form a floating biofilm sustained by oxygen at the wine–air interface.<ref>Ribéreau-Gayon et al., ''Handbook of Enology, Volume 2'', Wiley, 2006, ISBN 9780470010396.</ref> | ||
Unlike fermentative yeasts, flor strains metabolise ethanol, glycerol and organic acids rather than sugars, producing compounds such as [[acetaldehyde]] that contribute to the wine’s characteristic aroma profile.<ref>Waterhouse | Unlike fermentative yeasts, flor strains metabolise ethanol, glycerol and organic acids rather than sugars, producing compounds such as [[acetaldehyde]] that contribute to the wine’s characteristic aroma profile.<ref>Andrew L. Waterhouse, ''Understanding Wine Chemistry'', Wiley, 19 Aug. 2016. ISBN 9781118627808.</ref> | ||
== Conditions for development == | == Conditions for development == | ||
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== Role in biological ageing == | == Role in biological ageing == | ||
During biological ageing, flor acts as both a protective and transformative agent. By consuming oxygen, it limits oxidative reactions, preserving pale colour and freshness. Simultaneously, yeast metabolism alters the wine’s chemical balance, reducing glycerol and producing volatile compounds that define flor-aged styles.<ref>Boulton | During biological ageing, flor acts as both a protective and transformative agent. By consuming oxygen, it limits oxidative reactions, preserving pale colour and freshness. Simultaneously, yeast metabolism alters the wine’s chemical balance, reducing glycerol and producing volatile compounds that define flor-aged styles.<ref>Roger B. Boulton, Vernon L. Singleton, Linda F. Bisson, Ralph E. Kunkee, & 1 more, ''Principles and Practices of Winemaking'', Springer, 31 Oct. 1998. ISBN 9780834212701.</ref> | ||
The resulting wines are typically dry, light-bodied and marked by aromas often described as almond, bread dough and green apple, distinct from the nutty and caramelised notes associated with oxidative ageing.<ref>Peynaud, ''Knowing and Making Wine'', Wiley, 1984, ISBN 9780471881491.</ref> | The resulting wines are typically dry, light-bodied and marked by aromas often described as almond, bread dough and green apple, distinct from the nutty and caramelised notes associated with oxidative ageing.<ref>Peynaud, ''Knowing and Making Wine'', Wiley, 1984, ISBN 9780471881491.</ref> | ||
== Stylistic expression == | == Stylistic expression == | ||
Flor ageing underpins the identity of | Flor ageing underpins the identity of Fino and Manzanilla, while also forming the first stage in the production of [[Amontillado]], where biological ageing is followed by oxidative maturation after the flor layer dissipates.<ref>Karen MacNeil, ''The Wine Bible'', Workman Adult, October 11, 2022. ISBN 9781523510092.</ref> | ||
The thickness, continuity and longevity of flor influence stylistic outcomes, with thinner or intermittent flor leading to greater oxidative influence and structural development over time.<ref>Lawless, ''Wine Faults'', Mitchell Beazley, 2013, ISBN 9781845337233.</ref> | The thickness, continuity and longevity of flor influence stylistic outcomes, with thinner or intermittent flor leading to greater oxidative influence and structural development over time.<ref>Lawless, ''Wine Faults'', Mitchell Beazley, 2013, ISBN 9781845337233.</ref> | ||
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Flor ageing is formally recognised and regulated within the framework of fortified wine production. The [[OIV]] defines biological ageing as maturation under yeast film in the presence of oxygen, distinguishing it from oxidative ageing processes.<ref>OIV, “Biological ageing under flor”.</ref> | Flor ageing is formally recognised and regulated within the framework of fortified wine production. The [[OIV]] defines biological ageing as maturation under yeast film in the presence of oxygen, distinguishing it from oxidative ageing processes.<ref>OIV, “Biological ageing under flor”.</ref> | ||
Such definitions underpin appellation rules in Sherry and related regions, ensuring consistency of style and terminology in international wine law.<ref>OIV, “Fortified wine definitions”.</ref> | Such definitions underpin appellation rules in [[Sherry]] and related regions, ensuring consistency of style and terminology in international wine law.<ref>OIV, “Fortified wine definitions”.</ref> | ||
== Historical context == | == Historical context == | ||
The deliberate use of flor in wine ageing emerged in Andalusia over several centuries, evolving from empirical cellar practices into a defining technical feature of Sherry production. Its recognition marked a crucial divergence from earlier oxidative ageing traditions in fortified wines.<ref>Unwin, ''Wine and the Vine'', Routledge, 1991, ISBN 9780415042698.</ref> | The deliberate use of flor in wine ageing emerged in [[Andalusia]] over several centuries, evolving from empirical cellar practices into a defining technical feature of Sherry production. Its recognition marked a crucial divergence from earlier oxidative ageing traditions in fortified wines.<ref>Unwin, ''Wine and the Vine'', Routledge, 1991, ISBN 9780415042698.</ref> | ||
Modern microbiological research has since clarified the genetic and metabolic specificity of flor yeasts, reinforcing their central role in one of the world’s most distinctive wine styles.<ref> | Modern microbiological research has since clarified the genetic and metabolic specificity of flor yeasts, reinforcing their central role in one of the world’s most distinctive wine styles.<ref>Kenneth C. Fugelsang, ''Wine Microbiology'', Springer, July 31, 1997. ISBN 9780412066115.</ref> | ||
== See also == | == See also == | ||