For the production of its single malts, Glenfiddich uses a careful selection of malted barley to which Robbie Dhu spring water heated to 64° is added. From this mash, the process of extracting all the sugars begins, which will be transformed into alcohol during fermentation. Glenfiddich 12 is distilled in copper pot stills and aged for a minimum of 12 years in ex-sherry and American oak barrels.