Botrytis Cinerea – The Magical Mushroom

By Thomas Laszlo

Pictures: The three pictures show the progressive stages of Noble Rot used in making our 2005 Select Late Harvest Chardonnay. The process from healthy grape to Noble Rot usually takes two weeks. At any time during that period all hopes of a great wine can be lost by an excessive rainy period rendering the grapes useless except for green fertilizer when they drop to the vineyard floor!

Often in growing grapes there is a balance that exists between phenomenal quality and complete disaster. As winemakers and viticulture managers we dance a quiet ballet with Mother Nature, the Laws of Chemistry and artistic drive to create something that is unique with the ability to awe the taster. At times this ballet can turn quickly into a war that requires an exacting strategy of offenses and defenses in order to achieve a wine of awe. The making of top flight Noble sweet wine from the Botrytis Cinerea fungus presents the winemaker with the biggest challenge, more than any other style of wine that exists. A vintage that holds a promise of sublime sweet wine usually has the winemaker dancing the effortless ballet but on a dime it can turn to all out war!

In almost all cases of red and white wine winemaking, one of the most dreaded grape diseases is an attack of Botrytis Cinerea. In red wines the fungus causes off flavors with a dramatic loss in color and flavor (called Grey Rot). In dry whites the fungus can totally overcome the berry in fur (known as conidia) causing vinegar flavors along with oxidized mushroom flavors (known as Sour Rot). For the most part no sane grapegrower wants their grapes attacked by Botrytis. However, if the Botrytis attacks already ripe white grapes with a high sugar content and there is just the right amount of moisture for the fungus to form but not overcome the berry, then the most magical incarnation of Botrytis Cinerea occurs (Noble Rot).

How Noble Rot Occurs

The ultra ripe berries that are formed in very dry, hot vintages contain a high sugar content to start. A slight attack of Noble Rot occurs in the already very sweet healthy berries. The mold pierces the berries with its fungal hyphae leaving microscopic holes. The rot dies quickly because it can not handle the high osmotic pressure from the elevated sugar content and dryness. Then once the berry is pierced evaporation occurs. If the weather remains dry and hot the berries will shrivel and are often harvested in mid- October which is really not that late. In the best versions of Noble Rot, the Botrytis doesn’t progress enough to take away too much varietal character. The end result is a very concentrated, varietal wine that is high in sugars and acid. Often the shriveled, raisin like berries are selected berry by berry or are cut out in small clusters from the larger bunch. While the berry is a little furry and kind of brownish-purplish and may not appeal to some, the brave who taste it are amazed at the honeyed, tropical, concentrated yumminess.

Brief History of Noble Rot

For five years I was privileged to work with the world’s top Noble Rot wines in Tokaj, Hungary as the Head Winemaker for Chateaux Pajzos and Megyer. Each great wine has a story that borders on legend. Legend states that Aszú, (botrytis affected berries), were discovered in the early 1600s when the threat of an Ottoman Turkish invasion to the Tokaj region forced the ruling Transylvanian Princes of Hungary to send all able-bodied peasants to ward off the attack thus delaying the harvest into late fall. When the grapes were finally harvested, the Noble Rot had set in the berries. It was not until the following Easter when the wine was pulled from the cellars and tasted, that they realized the Botrytis jewel that had been uncovered.

In Germany the rot is called Edelfäule, in France it is known as Pourriture Noble, in Tokaj as Aszú and in the New World it is Noble Rot. Botrytis wines are some of longest lived wines in the world. It is not uncommon for the wines to improve for decades and sometimes centuries! I had the great fortune in Tokaj to taste an 1911 Esszecia. The wine had a natural sugar content of 60% and had been aged in barrel for 40 years before being bottled. While it was quite dark in color (think molasses) the wine displayed an incredible panoply of heady flavors ranging from dried apricot and figs to honeyed exotic spices. The mouth finish lasted for at least a half hour. It was truly a life altering moment in time!

Heron Hill Winery 2005 Select Late Harvest Chardonnay

The occurrence of Noble Rot in the Finger Lakes is certainly rare. The varieties most often affected are Riesling and Vignoles. The growth of Botrytis Cinerea in Chardonnay is most often viewed as a negative because seldom does Chardonnay achieve the necessary hang time needed to produce Noble Rot. Due to Chardonnay’s thin skin and relatively early ripening period, an infection of Botrytis usually means “Sour Rot” which renders the affected grapes unusable. Having made Botrytis affected dessert wines in three different countries from several different varieties, I have longed to make a Botrytis Chardonnay. Finally my wish came true. On October 31st 2005 a near perfect, complete infection of Noble Rot occurred with Chardonnay at the Ingle Vineyard.

Limited quantities of this once in a lifetime wine are still available at the winery and the website. The wine is still in an embryonic stage and will continue to develop gracefully over the next 20 years for sure!

For more information on the Heron Hill Winery 2005 Select Late Harvest Chardonnay, click here.