This step is very important to the assemblage of the wine. It consists of seeking out among the different vats of the vintage those that qualify for making the "grand vin." One must single out the best vats of the Cabernet Franc, Cabernet Sauvignon and Merlots and make sure that the resulting synergy of their blending will develop great harmony as well as complexity in the resulting wine. This step comes after the alcoholic and malolactic fermentation is finished.

Numerous trial blendings are necessary in judging the quality of the wine. The tastings progress gradually until finally one decides on the best blend. Little by little the "grand vin" has emerged with : the best equilibrium, the most perfect harmony, and the complexity of aromatic characteristics that are found year after year in the wines of Haut-Brion.