Botrytis cinerea transforms ripe grapes into precious sweet-wine delicacies. Find out how a mould becomes liquid gold.
Aromatic profile may vary depending on climate, soil and winemaking.
Botrytis cinerea is a fungus that, under specific climatic conditions, attacks wine grapes and triggers a fascinating transformation. While the fungus can wreak devastating damage as "grey rot" in humid conditions, under ideal circumstances it develops into so-called noble rot (French: pourriture noble) – the key to the world's most precious sweet wines.
The development of Botrytis into noble rot requires a specific microclimate:
These conditions are found particularly along riverbanks (e.g. the Mosel, Sauternes on the Garonne) or in regions with morning mist and afternoon sunshine.
The Botrytis fungus penetrates the berry skin with microscopic hyphae (fungal threads) and triggers several chemical changes:
The result: a highly concentrated, aromatically complex must that is vinified into exceptional sweet wines.
The sweet wines of Sauternes, above all Château d'Yquem, are the ultimate expression of noble-rot wines. The primary grape Sémillon is particularly susceptible to Botrytis and develops intense honey, apricot, and saffron aromas.
German Riesling Trockenbeerenauslesen are among the rarest and most expensive wines in the world. These concentrated, nobly sweet wines from the Mosel, Rheingau, or Pfalz combine extreme sweetness with vibrant acidity.
The legendary Tokaji from Hungary is made from noble-rot-affected Furmint and Hárslevelű grapes. The Aszú berries are harvested separately and added to the base wine – the more Puttonyos, the sweeter the wine.
Extraordinary sweet wines are produced in Alsace from noble-rot-affected Gewürztraminer, Riesling, and Pinot Gris. The Sélection de Grains Nobles (SGN) is the Alsatian equivalent of the German Trockenbeerenauslese.
Harvesting botrytis-affected grapes is extremely labour-intensive:
This demanding production process explains the high prices of Botrytis wines.
Wines made from noble-rot-affected grapes display a unique aromatic profile:
A characteristic, hard-to-describe scent – often described as "noblely fungal", "waxy", or "honey-wax-like". This typical Botrytis note makes the wines unmistakable.
Not every Botrytis infection is desirable:
Winemakers must monitor the weather closely to walk the narrow line between noble rot and grey rot.
Botrytis wines are among the longest-lived wines in the world:
The high concentration of sugar, acidity, and extract preserves the wines naturally.
Botrytis cinerea is a fascinating example of how nature can turn a potential pest into an enrichment. Noble rot transforms ordinary grapes into liquid gold and enables sweet wines of unrivalled complexity and elegance. Every sip of a noble-rot wine is a gift from nature – rare, precious, and unforgettable.
Botrytis cinerea is a mould that attacks wine grapes. Under damp conditions it causes damage as "grey rot", but under ideal conditions it develops into noble rot (French pourriture noble) – the key to the world's most precious sweet wines.
Grey rot occurs in persistently wet weather, destroys the grapes completely and leads to musty aromas. Noble rot arises with the ideal alternation of damp and dry, concentrates sugar and aromas and creates complex, honeyed notes – the basis for top sweet wines.
The fungus penetrates the berry skin and causes several changes: the berries lose up to 80% of their water and shrivel like raisins, the sugar content rises to 30-40% (normally 15-25%), the acidity is partly broken down and new aromas such as honey and dried apricots emerge.
Among the most famous botrytis wines are Sauternes and Barsac from Bordeaux (above all Château d'Yquem), German Riesling Trockenbeerenauslesen, the Hungarian Tokaji Aszú, as well as the Sélection de Grains Nobles (SGN) from Alsace.
They show a unique aroma profile of dried apricots, honey and beeswax, raisins and candied fruit, plus orange marmalade, saffron and nuttiness. Characteristic is the hard-to-describe botrytis note, often described as "noble-fungal" or "waxy".
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