During the latest two quaternary ice-ages, the tertiary oligocene formation has been cut out by the Seignal river and its small tributary the Fonchotte. The result of it undercovers a very hard lacustrian calcareous soil : "le calcaire de Castillon". The Château Pierrail vineyard has been set in the slopes of this rocky valley. Thus it benefits from a shallow soil (rendzine), slightly thicker at the bottom of the slope, with a continuous granulous structure, stony and resting on the draining roc..
The Fonchotte runs along side the vineyard from south-west to north-east. This gives the vines a SOUTH-EAST exposure "which provides the best results as it receives the rays from the early morning sun. Consequently the air temperature gets higher earlier" (P. Galet)."