What is Noble Rot?

Botrytis Cinerea or also known by the name Noble Rot is a form of grey fungus which grows on certain types of fruits.

This fungus is brought on by moist, wet conditions, at which point is known as Grey Rot. The Noble Rot fungus sometimes actually helps wine in producing a sweeter wine. Grapes usually become infected when they are ripe. Once infected and exposed to drier conditions, the grapes become raisined and this is known as Noble Rot. Some wine producers use this technique purposely to produce sweeter wines.

The origin of using infected grapes can date back to around 1570 but the vineyard classifications began in 1730 in the Tokaj region in Southeastern Slovakia. Many crops are lost to Grey Rot but many distinctive sweet dessert wines like Tokay, Tokaji, Aszu, and Sauternes are among those produced from the Noble Rot grapes.

The name Botrytis cinera comes from Latin and translates to “Grapes like ashes” which is in reference to their color. The fungus removes water from the grapes leaving high amounts of sugars, acids, and minerals. The more concentrated the product is the more intense flavors it has. Besides grapes, Noble Rot affects many other plants like strawberries, tomatoes, etc.

It has been shown that field workers who pick the Noble Rot grapes can be subjected to a rare form of hypersensitivity pneumonitis (winegrower’s lung).

Popular myths

There are many stories behind the practice of making wine from Noble Rot which include a story about a Riesling producer at Schloss Johannisberg in the Rheingau region who awaited the approval of the estate owner before cutting the grapes. The owner was Heinrich von Bibra, bishop of Fulda and he sent his abbey to give the message to harvest but was robbed en route to deliver the message and so the harvest was lost to the rot and given to the peasants who made a sweet delicious wine from these grapes known as Spatlese or “late harvest” wine.

Further reading: What is Full Bodied Wine?

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