This article proposes and studies the effectiveness of grape variety diversification as a risk management strategy. Using a sample of 5,679 harvested quantity and quality observations from the Valais region of Switzerland over the vintages 2003 to 2017 we document that quantitative and qualitative variations between vintages are significantly influenced by climatic conditions. The diverging and uncorrelated variations displayed amongst grape varieties suggest a potential diversification effect. We report a considerable reduction in crop risk when a grape variety is added to a portfolio of existing varieties. Diversification thus allows wine producers to manage some of the climate risk they face.