The vineyard of Cos spreads around the château on 173 acres. It is split into about 30 parcels of land.

In the old Gascon language, the word 'Cos' means 'The Hill of Pebbles'. And as a matter of fact, the hill of Cos, which is situated on the banks of the Gironde, is an impressive accumulation of Quaternary gravel wrested from the distant mountains of the Massif Central and the Pyrenees and laid on Saint-Estèphe's limestone bed when the primeval river receded.

The Cabernet Sauvignon vines (60% of the vineyard) find the soil of their choice in the thin layers of gravely soil situated on the top and on the southern slopes of the hill.

On the other hand, the Merlot vines (40% of the vineyard) excel on the eastern slopes and on the slopes where the Saint-Estephe limestone bed shows on the surface.

The percentage of Cabernet and Merlot varies from one vintage to another according to the year weather conditions, benefiting successively to the one or the other.

Plantation is extremely dense (8000 to 10000 vines per hectare) and the average age of the vineyard is high (35 years old on the average) in order to enable the roots to extend excessively and to obtain a very slender yield per vine that will create the "Grand Goût"

Only the wines made from the vines over twenty years of age will bare the name of Château Cos d'Estournel

Each vine grower is in charge of 45 000 vines on which they have got to undertake various labours every year. These cultural tasks are for most of them done manually.

The harvest is of course manually picked too. And it is by hand that the grapes, once collected in special wooden baskets, will be strictly selected.