The wine spends 42 days in oak barrels on fine lees at the beginning of the winemaking process. The production of 42 Zura begins with the must of Hondarrabi Zerratia grapes. The clarified must is poured into fine-grain French oak fermentation barrels from the Allary cooperage in France. The must undergoes a long cold fermentation before being racked and stored for approximately 7 more months on its lees in stainless steel. Finally, after a series of rackings and decantings for at least another 4 months, the wine is bottled.