Château de Saint Cosme Côtes-du-Rhône Blanc Le Poste is from a 1-hectare terraced vineyard that sits near the chapel of Saint Cosme, a short uphill climb from the winery. The maximum elevation is 280 meters, 140 meters above the Gigondas valley floor, and is one of the coolest vineyards in Gigondas. The terraces and elevation make it necessary to plow the vineyard by horse.

The vineyard was replanted in 1963 by Henri Barruol to a field blend based mainly on Grenache and one small parcel of Clairette from which Le Poste Blanc is produced. This 100% Clairette was vinified in used traditional demi-muids without malolactic fermentation and aged 10 months on lees.