In most regions where walnut trees grow, the tradition is to macerate green walnuts picked on St. John's Day either in wine or brandy. The Noix des Pères Chartreux is made according to an old Dauphinoise recipe. The green walnuts are of course picked on St. John's Day according to tradition, then macerated in alcohol. The Fathers also add a decoction of plants, which gives it its very particular aroma.
This walnut, between liqueur and wine, moderately alcoholic, can be enjoyed as an aperitif or digestif.