Little known 50 years ago, this château has seen the rise of a myth about the uniqueness of its wine. The wine’s inimitability is due to many factors including an exceptional terroir. The vineyard is 40 meters above sea level, the highest point of the appellation, and has a layer of heavy clay soil and an iron subsoil. These are ideal conditions for the expression of the Merlot grape. With such a special terroir, the approach in the vineyard and cellar is traditional and respectful.

The estate was among the first in Bordeaux to implement green-harvesting as a way to lower crop yields and raise the quality of the remaining grapes. The yield is among the lowest in Bordeaux partly through green-harvesting to concentrate the power and quality of the remaining crop (eliminating up to 50% of the crop in certain years).

The clay soils of Pétrus are at least 40 million years old. The thick gravel on the surrounding plateau is only 1 million years old. There are two layers of clay at Pétrus; the topsoil of dark clay is 60 to 80 centimeters thick. But it's the unique subsoil that is not found in any other vineyard. The soil is packed with very, dense, deep, dark blue clay. The clay is so hard, that the roots cannot penetrate. The clay is smectite. When this type of clay absorbs water, it becomes impermeable.

The grapes are picked by hand, de-stemmed, and then sorted. A gentle crush before vinication in concrete vats is followed by maceration, which typically lasts 15 to 21 days. After maceration, the juice heads to another vat for malolactic fermentation. Following fermentation, each vat is tasted and the qualifying juices are blended together before the wine is aged in French oak barrels, of which 50% are new (and filled with water prior to the wine to get rid of aggressive tannins). Once in barrel, the wines are racked every three months. The length of aging varies depending on the vintage. Prior to bottling, the wines are fined and filtered. 

Pétrus displays an intense color, a rich and complex nose and an opulent fruit. In great vintages, the wine can easily be kept 25 years or more.