Why deleafing/thinning is important for Pinot Noir in Oregon

Deleafing is the process of removing excess leaves as a part of vineyard management. This process is done primarily to provide ample ventilation and sunshine to the growing grape cluster during veraison (ripening of the grapes).

It is especially important in Oregon where there is high probability of rain, this would also allow the grapes to quickly dry and receive direct sunlight in order to avoid grape diseases such as mildew or botrytis which would lead to “bad” grapes. Pinot Noir is a an especially delicate grape variety and this additional exposure to sunlight and ventilation will also help it mature properly.