Noble rot – technical name, Botrytis cinerea (Boh-TRI-tihs Sihn-EHR-ee-uh) – is the fungus you want. It is a beneficial mold that develops on grapes under certain environmental conditions. When carefully cultivated, botrytis causes grapes to shrivel on the vine, concentrating and intensifying both sugar and flavor. Acidity levels remain high, which prevents the resulting wines from being cloyingly sweet. Most winemakers are exhilarated when noble rot descends on their grapes, because it gives them fruit for elegant, intensely-flavored dessert wines. (There is another form of the fungus, known as gray rot, which can ruin a crop.)
In California, botrytised (BOTT-treh-tized) wines are usually labeled as late-harvest. In France, where noble rot is called "pourriture noble," the best-known beneficiaries are the famous wines of Sauternes. Noble rot is called "Edelfäule" in Germany, where winemakers are experts at using it to produce a large variety of elegant wines such as Trockenbeerenauslese and Beerenauslese. The renowned Hungarian "Tokaji Aszú" is also a popular botrytis-infected wine.
These dessert wines are fantastic to sip on their own, but also complement an array of fruity desserts, especially those made with pears, apricots and peaches. Botrytised wines also make extravagant pairings with pâté and foie gras.