Wine 101: Terms: Noble Rot

This episode of “Wine 101” is sponsored by Orin Swift. In Napa Valley, Cab reigns supreme. Known for its big, bold, aged — over 30 years — entry in the category, the Polermo Cabernet Sauvignon by Orin Swift is a defining example of the striking, powerful style Napa is known for.

Grapes are often at odds with Mother Nature’s more menacing side. Many forms of fungus and rot are detrimental to wine, but then there’s noble rot. The term may sound gross but we assure you, it’s a beautiful thing. And it’s essential for making some of the most age-worthy wines in the world.

In temperate climates, a fungus called Botrytis cinerea lives on the sap of dying plant tissue as a saprophyte. As the humidity of summer works its way into autumn this fungus looks for weaknesses in grapes — weather damage or small tears from bugs and birds — where it can invade, eventually creating a gray film over the grape bunches. This, by the way, is where the word cinerea (Latin for “gray”) comes in.

When this “gray rot” occurs in full, it destroys the wine grapes, but if Botrytis cinerea attacks otherwise healthy grapes, and the sunlight is strong enough to evaporate any humidity, the fungus ceases to expand and prevents other fungi from entering the grape. Within each grape, Botrytis cinerea eats the majority of the acid content as well as a bit of sugar and develops new compounds in their place. Meanwhile, the grapes will become slightly shriveled and take on a brown, raisin-like hue. In the end, the grapes lose about half of their water content.

This, wine lovers, is called noble rot. It’s a delicate process, and winemakers have to be extra attentive when harvesting to pluck these grapes at the prime level of infection. To make up for the loss in acidity, vintners will add a mix of infected and non-infected grapes into the fermentation tank. The resulting wines tend to be high in acid with sweet notes of hazelnut and butterscotch.

On this episode of “Wine 101,” Keith gives the full rundown on noble rot and all the wonderful wines we can thank for it. As he says, “Noble rot is all about taking the malevolent and making it benevolent.” Tune in for more.

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“Wine 101” was produced, recorded, and edited by yours truly, Keith Beavers, at the VinePair headquarters in New York City. I want to give a big old shout-out to co-founders Adam Teeter and Josh Malin for creating VinePair. Big shout-out to Danielle Grinberg, the art director of VinePair, for creating the most awesome logo for this podcast. Also, Darby Cicci for the theme song. Listen to this. And I want to thank the entire VinePair staff for helping me learn something new every day. See you next week.

E. & J. Gallo Winery is excited to sponsor this episode of VinePair’s “Wine 101.” Gallo always welcomes new friends to wine with an amazingly wide spectrum of favorites, ranging from everyday to luxury and sparkling wine. (Gallo also makes award-winning spirits, but this is a wine podcast.) Whether you are new to wine or an aficionado, Gallo welcomes you to wine. Visit today to find your next favorite, where shipping is available.