Noble rot
Noble Rot (/ˈnəʊ.bəl rɒt/) refers to a beneficial form of the fungus Botrytis cinerea that affects ripe wine grapes under specific climatic conditions. While the same fungus can cause destructive grey rot, in its noble form it has long been prized for producing some of the world’s most celebrated sweet wines.[1] The term reflects the paradoxical transformation of decay into quality, a phenomenon particularly associated with regions such as Sauternes and Tokaji.
Background
Botrytis cinerea is a widespread mould that infects many fruit crops. In viticulture, its impact depends on weather and vineyard management. When conditions are persistently wet, it leads to destructive grey rot, which devastates yields. Under alternating humidity and sunshine, however, the fungus punctures grape skins, causing evaporation and concentrating sugars and acids in the berries.[2] This duality has been recognised in European vineyards for centuries, where noble rot has been harnessed to create distinctive dessert wines.
Characteristics
The development of noble rot requires a delicate balance of misty mornings, which allow the fungus to grow, followed by warm, dry afternoons that prevent uncontrolled rot.[3] The affected grapes appear shrivelled and often turn brownish or grey. Inside, their juice becomes unusually concentrated, with elevated levels of glucose and fructose, alongside intensified acidity and complex aroma precursors.[4] Wines produced from such grapes often display notes of honey, dried apricot, marmalade and saffron, together with remarkable longevity in the bottle.
Use in winemaking
Noble rot has become a defining element of certain historic wine styles. In France, it underpins the production of Sauternes and neighbouring appellations, where Semillon, often blended with Sauvignon Blanc, produces intensely sweet yet balanced wines.[5] In Hungary, it is central to Tokaji, where the local Furmint grape develops extraordinary complexity when affected. Germany and Austria employ the fungus in the making of Trockenbeerenauslese and Ausbruch wines, typically from Riesling.
The harvest of botrytised grapes is labour-intensive, requiring repeated passes through the vineyard to select only affected berries at the right stage. Yields are extremely low, and the concentration of sugars challenges fermentation, often resulting in wines with modest alcohol and pronounced sweetness.[6] Despite these difficulties, the style remains a benchmark of late-harvest winemaking, admired for its complexity and ageing potential.
See also
References
- ↑ Robinson (ed.), The Oxford Companion to Wine, Oxford University Press, 2015, ISBN 978-0198705383.
- ↑ Jackson, Wine Science: Principles and Applications, 5th ed., Academic Press, 2020, ISBN 978-0128161180.
- ↑ Stevenson, The Sotheby’s Wine Encyclopedia, 5th ed., DK, 2011, ISBN 978-0756686840.
- ↑ Peynaud, Knowing and Making Wine, Wiley, 1984, ISBN 978-0471881491.
- ↑ Johnson & Robinson, The World Atlas of Wine, 8th ed., Mitchell Beazley, 2019, ISBN 978-1784724030.
- ↑ Jackson, Wine Science: Principles and Applications, 5th ed., Academic Press, 2020, ISBN 978-0128161180.