Definition: botrytisation

Noble rot forms on ripe grapes due to the development of the Botrytis cinerea fungus under certain conditions of high humidity in the morning (morning mist) and relatively warm temperatures in the afternoon. The skin of the grape becomes thinner, causing water evaporation and the pulp to shrivel. The sugar content of botrytised grapes increases, but the berries become very delicate, requiring late harvesting with great care, often berry by berry and in successive passes.