The secret to the success of Le Vieux Donjon is really no secret at all. They have tremendously old vines (many in excess of 80 years of age) and they are experts at picking only once the grapes have achieved optimum ripeness. Partial de-stemming is practiced, as is a rather lengthy maceration. The juice is then fermented in cement tanks before spending 18-24 months maturing in neutral foudres. As is the case at Clos des Papes, only one cuvée is produced.