Grand-Puy-Lacoste is situated in the terroir of Pauillac, one of the Médoc's six communal appellations along the Gironde estuary's left bank.

The Pauillac appellation is limited to the communal district covering 2,274 hectares. It boasts 18 properties classified in 1855 (around 85% of the appellation's total production). The commune is separated from Saint-Estèphe to the north by the marshy area of Breuil, and from Saint-Julien to the south by the hollow formed by the Juillac stream.

The plateau of Grand-Puy is west of the village, above the hamlet of Bages. This outcrop of the terrain (called a "puy" in the old local dialect) rises to around 20 meters above sea level.

The site possesses a number of major benefits: the quality of the soil, a favorable climate, the experience and expertise of its people. The result is a unique conjunction of forces...

Grand-Puy-Lacoste enjoys an exceptional terroir. The soil is gravel, the alluvial stones which ensure an excellent drainage of rainwater.

The originality of the Médoc's soil comes from two million years of history. Its gravel is the geological product of the quaternary era, when stones brought from the Pyrenees by the Garonne were deposited along the banks of its estuary, the Gironde.

Today layers of varying depth are composed of gravel mixed with sand and a little clay. They form "gravel outcrops”, separated by small streams called "jalles” in the local dialect which drain water to the Gironde. In Pauillac these vast and numerous outcrops are recognized as being particularly well-suited for top quality vine growing.

This gravely soil has the advantage of absorbing heat during the day and releasing it to the grapes at night, eliminating excessive variations in temperature and promoting even ripening in the grapes.

The vineyards of Grand-Puy-Lacoste are planted on very deep gravel, forcing the plants to develop an extensive root system to find the water and nourishment needed for growth. Because of the soil's poor quality, the vines "suffer for their beauty” and become more resistant with age, producing fully developed grapes with a fine sugar-acid balance. Cabernet Sauvignon is particularly well suited for this type of soil: it's a late ripening variety which needs a longer period to reach maturity than Merlot, so the heat given off by the gravel helps accelerate its growth.

Like the totality of Pauillac's growths, Grand-Puy-Lacoste benefits from Aquitaine's oceanic climate which is greatly influenced by the proximity of the Atlantic and the Gironde estuary, particularly wide at this point.

Situated along the 45th parallel, the Médoc vineyards enjoy a very balanced climate marked by great sunshine, hot summers and mild winters. But this terroir is especially influenced by a unique phenomenon: winds coming from the ocean and the estuary which create a particularly favorable microclimate. Strong ocean winds cross the coastal pine forest and slow down as they meet air currents from the estuary, introducing a measure of humidity to the atmosphere.

The climate of the Pauillac appellation is shaped by its proximity to the Gironde, which has its own moderating influence on temperatures. At each stage of the vine's growth, from bud-break to the grapes' ripening and harvest, climate variations define the harvest's character. The finest vintages are always the product of a hot and dry summer, followed by a fine late-growing season.

The date of picking is carefully studied according to the maturity of the fruit, which must be optimal.