Noble rot

Noble rot (French: pourriture noble; German: Edelfäule) is the benevolent form of a grey fungus, Botrytis cinerea, affecting wine grapes. Infestation by Botrytis requires moist conditions, and if the weather stays wet, the malevolent form, "grey rot", can destroy crops of grapes. Grapes typically become infected with Botrytis when they are ripe, but when then exposed to drier conditions become partially raisined and the form of infection brought about by the partial drying process is known as noble rot. Grapes when picked at a certain point during infestation can produce particularly fine and concentrated sweet wine. Some of the finest Botrytized wines are literally picked berry by berry in successive tris (French for "selections").  

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Origins

According to Hungarian legend the first aszú (a wine using botrytised grapes) was made by Laczkó Máté Szepsi in 1630. However, mention of wine made from botrytised grapes had already appeared in the Nomenklatura of Fabricius Balázs Sziksai which was completed in 1576. A recently discovered inventory of aszú predates this reference by five years. When vineyard classification began in 1730 in the Tokaj region, one of the gradings given to the various terroir centered around their potential to develop Botrytis cinerea.

A popular myth is that the practice originated independently in Germany in 1775, where the Riesling producers at Schloss Johannisberg (Geisenheim, in the Rheingau region) traditionally awaited the say-so of the estate owner, Heinrich von Bibra, Bishop of Fulda, before cutting their grapes. In this year (so the legend goes) the abbey messenger was robbed en route to delivering the order to harvest and the cutting was delayed for three weeks, time enough for the Botrytis to take hold. The grapes were presumed worthless and given to local peasants^[1] who produced a surprisingly good, sweet wine which subsequently became known as Spätlese, or late harvest wine. In the following few years, several different classes of increasing must weight were introduced and the original Spätlese was further elaborated, first into Auslese in 1787^[2] and later Eiswein in 1858.^[3]

Viticulture and uses

The Tokaj-Hegyalja region of Hungary is the most famous^{[citation needed]} producer of botrytised wine, being noted above all for its aszú wines. Sauternes (France) and Beerenauslese or Trockenbeerenauslese (Germany) are the other globally-recognised wines made using botryrised grapes. Less famous^{[citation needed]} wines of this type include the Italian Amarone, Romanian Grasă de Cotnari, French Monbazillac and Austrian Ausbruch. Depending on conditions the grapes may be only minimally botrytized. Botrytis has also been imported for use by winemakers in California and Australia. In some cases inoculation occurs when spores are sprayed over the grapes, while some vineyards depend on natural inoculation from spores present in the environment.

References