“…In the Douro, heat and water stress at critical periods of the growing season represent a major constraint for wine quality and production (Hardie and Considine , Moutinho‐Pereira et al ). Other important forcing factors remain invariant between years, such as soils, cultural practices and cultivars grown (Hedberg and Raison , Fidelibus et al , Costantini et al , Renouf et al , Kamiloglu , Tardaguila et al , Fraga et al ). The relevance of climate and weather conditions for wine production in the DDR is highlighted by the existence of a ranking system for vineyard plots (from A, the best class, to F), in which climate has a strong weight.…”