When conditions are just right, nature can hold a usually nasty fungus in such check that something special happens. Instead of destroying a crop, the fungus creates grapes with incredibly concentrated flavor that can make some of the world’s sweetest, most precious wines. The fungus, Botrytis cinerea, is more affectionately known as “noble rot.” It’s the same kind of rot that spoils strawberries and soft fruit with greyish fuzz. So what makes this mold noble? It comes down to a fine balance of moisture, sunlight and temperature. Ripe, healthy grapes must still be on the vine as fall begins, when misty mornings can provide the moisture that the fungus needs to thrive. It will pierce a grape’s skin to feast on its juice. After a few hours, sunshine and otherwise dry conditions must follow. This evaporates moisture and stops the fungus in its tracks. The following morning, the process repeats itself. A succession of misty mornings and dry, sunny days provide the perfect conditions as sugars, flavors and acids concentrate in the grape while the fungus consumes water. It’s risky business, as rain can turn this delicate interaction into full-blown rot. In some years, growers lose their entire crop. Botrytized grapes aren’t pretty, as they turn shriveled and brown. Their juice, however, is golden, sweet and precious. Each grape needs to be handpicked individually, and yields are tiny. The resulting wines are complex, concentrated and can age for decades. In a few places, the crucial elements responsible for botrytis occur year after year, and all are famed for their noble sweet wines. Here are some of the best. —Anne Krebiehl, MW Tokaj The Tokaj-Hegyalja region in northeast Hungary and southeast Slovakia is said to be home to the oldest botrytized wines in the world, known as Tokaj or Tokaji Azsú (which historically meant “dried” in Hungarian, though today it’s almost exclusively associated with wines made from noble rot). Slopes that bear Furmint, Hárslevelű and Yellow Muscat, the three main grapes of Tokaj, receive early morning fog that wafts off the nearby Tizsa and Bodrog rivers. This creates ideal conditions for botrytis. The shriveled grapes are harvested separately in 20-liter buckets called puttonyos. A paste made from these crushed grapes is added to base wine produced from unbotrytized grapes, and then a second fermentation takes place in barrel. Traditionally, the number of puttonyos used has been proportional to the sweetness level of Tokaji, with six puttonyos at the top of the scale and five puttonyos slightly less sweet. Wines that were previously designated three or four puttyonos are now labeled late harvest or szamorodni. The sweetest Tokaji, Eszencia, uses the free run juice of azsú berries. Eszencia wines have extremely high sugar content, typically 500–700 grams per liter, and low alcohol. Classic pairings for Tokaj include foie gras (Hungary is the world’s leading producer) or Hungarian crepes. —Jeff Jenssen Patricius 2006 Aszú Six Puttonyos (Tokaj); $65/500 ml, 95 points. Tantalizing aromas of apricot, bananas foster, beeswax and pineapple upside-down cake transfer seamlessly onto the palate. It then opens up further, with pronounced flavors of lemon meringue and acacia honey. The texture is luxurious, silky and voluptuous. Blue Danube Wine Co. Editors’ Choice. Samuel Tinon 2007 Dry Tokaji Szamorodni (Tokaj); $46/500 ml, 92 points. Amber in color, with aromas of caramel and dried raisins. Rich flavors of dried fruits, stewed plums and wine-soaked raisins combine before a juicy yet persistent finish. Blue Danube Wine Co. Austria In Burgenland, which lies in Austria’s warmer east, one body of water creates perfect conditions for botrytis: Lake Neusiedl. The shallow lake ensures misty mornings with enough moisture for botrytis to develop. The villages on its shore have long been famed for their sweet wines. The town of Rust even used local sweet wine, known as ausbruch, to buy its free town status from the Austrian emperor in 1681. Heidi Schröck is one producer that still makes Ruster Ausbruch today, which can only be made in Rust. According to Schröck, the varieties best suited to making fully botrytized ausbruch are late-ripening Welschriesling and Furmint, for their piquancy and acidity, and Pinot varieties, for their creaminess. She usually harvests just 160 liters of juice per acre, which is painfully low and explains some of the lofty price tags on these rare wines. Less botrytis-affected grapes are made into spätlese and auslese styles. Located on the opposite, eastern shore of Lake Neusield in the town of Illmitz is Weinlaubenhof Kracher. Gerhard Kracher, who manages the family estate, believes that Welschriesling, Chardonnay, Scheurebe and Muskat Ottonel are best suited to make fine trockenbeerenauslesen, or TBAs, on the local soils. Even the red grape Zweigelt makes lovely botrytized wines, he says. Some of Kracher’s vineyards are less than 1,000 feet from the lake. While botrytis comes every year, he has to wait for the right conditions, which means harvest can take place anytime from October to December. Kracher suggests to serve TBA or ausbruch in a white wine glass at 54°F, with classic pairings like blue or soft, washed-rind cheeses, goose liver parfait or Austrian desserts like apfelstrudel (apple strudel), marillenknödel (sweet apricot dumplings) or pancakes with apricot jam. Schröck proposes more adventurous matches, something she signals on her quirky labels. She fights to get these sweet wines out of the cheese or dessert corner. “Depending on the acidity and character of the wine, other dishes work well,” she says. “Especially high-acid wines pair well with saltiness, ginger, chili and rosemary. Ausbruch can even work with peppered steak.” —Anne Krebiehl, MW Kracher 2013 Scheurebe Trockenbeerenauslese Nummer 5 Zwischen den Seen (Burgenland); $95/375 ml, 97 points. Candied lime and lemon zest are bathed in the rich honey notes of full-blown botrytis. Candied quince and mandarin peel run circles around honeycomb and apricot jam. Terlato Wines International. abv: 9.5% Heidi Schröck 2014 Ruster Ausbruch Turner (Burgenland); $160/375 ml, 96 points. A blast of beeswax and honey provides heady lift. The palate is tooth-breakingly sweet, but it comes with that honeyed, candied-citrus thrill. Sufficient bright acidity counters the richness. The mouthfeel is full, oily and viscous, with notes of honeycomb and beeswax. Skurnik Wines, Inc. Gunter Triebaumer 2013 Ruster Ausbruch Welschriesling (Burgenland); $35/375 ml, 94 points. Scents of candied lemon and rich blossom honey are lifted and intense. A touch of smoky stone can be glimpsed before the sweetness takes over. Candied-citrus notes swish across the palate, which trails blossom, honey, nectar and candied peel. The finish is fresh and clean. Magellan Wine Imports.—A.K. Germany Kissed by edelfäule, as the malevolent fungus is known here, the great botrytized wines of Germany are defined by wonderful perfume and juicy, sweet fruit balanced against electric acidity. Riesling, with its precision, intense aromatics and complexities of fruit, spice and mineral, is considered the noblest of botrytis-friendly grapes here. While typically light in body and alcohol, they vary from the racy, lime- and slate-scented delights of the Mosel to riper, more tropical Rieslings of Rheingau, Nahe or Pfalz. The warmer regions of Rheingau, Nahe and Pfalz are also home to honeyed Scheurebe wines, with distinct blackcurrant and grapefruit notes. In the Franken region, Riesling, as well as varieties like Silvaner and Rieslaner, often yield more muscular yet sublimely herb-inflected wines. It’s no coincidence that Germany’s greatest botrytized wines originate from vineyards that overlook the Mosel, Rhine, Nahe or Main rivers and their various tributaries. Large bodies of water adjacent to vineyards moderate cool, northerly climates and allow grapes to ripen through an extended growing season. Mist formed by the rivers contributes humidity that encourages botrytis growth and the transformation of pristine grapes into shriveled fruit bombs of sugar, spice and acidity. To preserve primary fruit character and vibrant acidity, German winemakers typically avoid techniques like new oak fermentation and maturation, which alters aromas and flavors, or malolactic fermentation, which rounds the palate and softens acidic edges. Robert Weil, one of the Rheingau’s most prestigious winemakers, has long produced both dry and botrytized Riesling. According to Nicolas Pfaff, the winery’s export director, delicacies like fois gras are classic pairings for botrytized Riesling. Frequent travels around the globe with Weil, however, have given Pfaff a greater understanding into these wines’ dexterity. “I had a wine dinner in Bangkok, and it was just fantastic,” says Pfaff. Pairing perfumed, sweet-and-spicy Thai cuisine with only spätlese, auslese and beerenauslese wines (all concentrated in sweetness by botrytis) resulted in a fascinating explosion of flavors, he says. —Anna Lee C. Iijima Robert Weil 2015 Kiedrich Gräfenberg Riesling Trockenbeerenauslese (Rheingau); $775/375 ml, 98 points. Layers of spicy saffron, peach, honey and caramel on the nose. The sweet-tart palate is deft and spry, yet it’s deep and lush in flavor. Spine-tingling acidity darts through a honeyed, waxy finish. It will continue to improve for decades. Loosen Bros. USA. Cellar Selection Dr. Loosen 2006 Graacher Himmelreich Riesling Beerenauslese (Mosel); $174/375 ml, 95 points. Feather-light in texture yet deeply penetrating in flavor, this offers rolling waves of sweet caramel, honey and stone fruit flavors. It’s luscious and mouthfilling in texture, but it’s balanced by strikes of lime acidity and a dry, pristine finish. Loosen Bros. USA. Editors’ Choice Dr. H. Thanisch (Erben Müller-Burggraef) 2015 Berncasteler Doctor Riesling Auslese (Mosel); $50/375 ml, 92 points. Pristine honey and tangerine sweetness falls on the palate in a delicate pattern here. It’s breathtakingly light in body yet unctuous and concentrated. Sunny citrus acidity leads a long, slightly spicy finish. Winesellers, Ltd. Loire Valley The beauty of botrytis is that it’s rare. Only two regions of the Loire Valley (which surrounds the Loire, France’s longest river) are designated as consistent enough to make botrytized wine: Layon River Valley (a Loire tributary) and Vouvray, on the Loire. Both rely on thin-skinned Chenin Blanc that balances crisp delicacy and extreme richness. Several appellations capture essential morning mists from the steep Layon riverbanks, which include Coteaux du Layon and village-designated Coteaux du Layon, such as Beaulieu, Chaume, La Faye or Saint-Aubin. The greatest selections, however, are from Quarts de Chaume (Loire’s only grand cru) and Bonnezeaux. Vouvray, 80 miles up river, produces every style of white wine from versatile Chenin Blanc. Botrytized wines are produced in small quantities and are frequently richer than those from the Layon. A visit to the limestone caves where the wines are stored reveals old vintages still full of life, which illustrates how well these opulent treasures can age. These are dinner wines. Both regions specialize in decadent cream sauces with local river fish, just right for the balance of richness and acidity found in the wines. —Roger Voss Château de Fesles 2011 Vin Rare (Bonnezeaux); $40/500 ml, 95 points. A golden wine that balances intense acidity with honeyed botrytis flavors. Ripe peaches and pineapples dominate the fruit profile of this concentrated, beautiful wine. It’s just approaching its peak, so wait until 2018. Advantage International. Editors’ Choice Domaine du Petit Métris 2014 Grand Cru (Quarts de Chaume); $65/500 ml, 94 points. This wine, with its opulent honey and spice character, is full of yellow fruit notes, and it keeps freshness that lifts the richness of the wine. This wine is still very young, so don’t drink before 2022. Boutique Wine Collection. Cellar Selection Bordeaux and Southwest France Sauternes is rooted in fluvial white-pebble and limestone outcrops that enhance the magical combination of Sémillon and Sauvignon Blanc. South of the city of Bordeaux, it’s a land of winding roads, crumbling stone walls and majestic fortresses. The wine’s sweetness is thanks to the meandering Ciron River that emerges from the pine forests of the Landes. The river carries its moisture and autumnal morning mists before it continues into the nearby Garonne river. On the other bank of the Ciron is Barsac, with similar but softer alluvial terraces. It’s the equal of Sauternes in the production of magnificent botrytized wines. Barsac offers delicate wines of great finesse, as opposed to the more powerful selections from Sauternes. Together, these appellations make some of the greatest botrytized wines in the world, like Yquem, Rieussec, Suduiraut, Climens and Coutet. Sauternes and Barsac are capable of aging for decades. Within the greater Southwest, two appellations are worth exploration for reasonably priced botrytized gems that fly under the radar. Monbazillac, on the Dordogne River, offers a lighter taste from the same white grapes common to Bordeaux. Gaillac, located on the Tarn River northeast of Toulousse, relies on Mauzac for its botrytized wines. In Bordeaux and the Southwest, these are not widely considered dessert wines, but instead are served as an apéritif that’s accompanied by local foie gras. —Roger Voss Château Coutet 2011 Barsac; $84, 96 points. Well balanced, this gorgeously ripe wine is packed full of fresh yellow fruits, ripe oranges and lemon. The fruit counterpoints the generous, dense structure that offers the dry core of botrytis. Acidity gives a line of freshness at the end. Drink from 2020. Millesima USA. Domaine de Grange Neuve 2011 La Fleur Lily (Monbazillac); $19/500 ml, 90 points. This is a fine, yet ripe, wine. It has an intense botrytis character that balances dryness with considerable sweetness. The wine, rich in honey and marmalade flavors, is opulent, decadent and ready to drink. LVC Las Vegas Inc. Editors’ Choice. Alsace In Alsace, a region in northern France, wines made from fully botrytized grapes are known as Selection des Grains Nobles (SGN), which is French for “selection of noble berries.” They’re made from Riesling, Pinot Gris, Gewurztraminer and Muscat, and while they’re very sweet, the best examples also exhibit high acidity for balance. Thomas Muré, of Domaine René Muré, says that for a good SGN, “botrytis must develop on ripe grapes. If that happens early in the season, you get fresh aromas with higher acidity.” The varieties permitted for SGN produce markedly different wines, says Muré. “Riesling, my favorite, makes crystalline wines,” he says. “Muscat is floral. Pinot Gris is very rich and has lots of candied fruit notes, while Gewurztraminer turns out very exotic, with delicate notes of rose.” Grapes partially affected by botrytis can be made into a Vendanges Tardives, or late-harvest wine. While sweet, they are lighter, milder and more versatile than SGNs. Muré typically matches SGNs with blue cheeses and aged, hard cheeses, and he’s even paired Riesling SGN with feathered game. —Anne Krebiehl, MW René Muré 2010 Vorbourg Grand Cru Clos Saint Landelin Vendanges Tardives Gewurztraminer (Alsace); $65, 95 points. Ripe peach hits the nose at once, followed by glimpses of marmalade and peach compote. The palate follows with the same aromatic intensity, which enriches the peach compote notes even further with lemony barley sugar and fresh caramel, pierced by tangy citrus acidity. Drink now through 2030. Gargouille Collection. Domaine Barmès-Buecher 2007 Hengst Grand Cru Sélection de Grains Nobles Gewurztraminer (Alsace); $145/500 ml, 94 points. A wealth of notions hits the palate: baked apple, fir honey, lemon-scented caramel and burnt sugar. Caramel-crusted apricots glow on the palate, while everything is lit up with bright, fresh acidity that highlights apricot, apple and honey. Petit Pois.