botrytis

Noble rot (scientific: Botrytis; French: pourriture noble; Italian: muffato) is a specific kind of mold that grows on grapes in the late season, reducing the water concentration and increasing the sugar concentration of the grape, and thus originating sweet wines such as Sauternes. Usage: associate if the beer has been aged in barrels used for such wines, or if the noble rot grapes have been added to the wort.