The exfoliation of the grapes is a quality-enhancing measure in the vineyard. The grapes are better ventilated after removing a portion of the leaves and dry faster after rainfall. As a result, the grapes are less prone to diseases such as botrytis. On the other hand, in hot summers, the lack of sun protection increases the risk of sunburn for the grapes. Some experts recommend exfoliation only on the side facing away from the sun.
This defoliation can be done by hand or by machine. Curiously, even sheep can eat the leaves. The grapes are still immature at the time and are therefore not eaten by the sheep.