Botrytization

Botrytization is the process by which ripe grapes are infected by the fungus Botrytis cinerea in a way that can concentrate flavors and sugars, producing distinctive botrytized wines. When the infection is favorable and controlled, the result is often called noble rot; if conditions are unfavorable, the same fungus can cause gray rot, which damages fruit and reduces quality.

The fungus colonizes grape skins, producing enzymes that break down cell walls and promote partial berry shriveling. This dehydration concentrates sugars and acidity, and can introduce complex aroma compounds. The resulting wines are typically very sweet, with high acidity and pronounced concentration, while the flavor spectrum may include honey, apricot, orange marmalade, peaches, and notes of spice or almond. Botrytized wines are frequently aged, gaining additional complexity over time.

Successful botrytization relies on specific microclimates. Mornings or autumn fogs moistens the vineyards to encourage Botrytis, followed by dry, mild days that allow partial drying without widespread rot. Such conditions are common in certain river valleys and hilltop sites, where grapevines can achieve ideal infection patterns without complete crop loss.

Notable botrytized wines include Sauternes and Barsac from Bordeaux, Tokaji Aszú from Hungary, and certain late-harvest wines designated Beerenauslese or Trockenbeerenauslese in Germany and Austria. Regions such as Austria, Germany, and France have historically developed styles and classifications around botrytized grapes, while other countries produce individual botrytized wines under various designations.

Botrytization remains a unique winemaking approach that bridges agricultural risk and meticulous vineyard management with the pursuit of intensely sweet, age-worthy wines.