TOPOGRAPHICAL CRITERIA :
To allow grapes to reach optimum ripeness and to limit risks of pests and diseases that can also prevent a high level of ripeness, only vineyard plots with a high capacity to dry out are eligible for cru status. Preference is therefore given to the steepest sloping terrain. Vineyard plots with a concave topography and vineyard plots with a slope of less than 2.5% are ineligible for the production of Cru Vallet wines.
PEDOLOGICAL CRITERIA :
In order to ensure that Cru Vallet berries have excellent concentration and to control vigour in the vines, thin soils are favoured. A regular supply of water is, however, sought throughout the growing cycle in order to avoid any excessive hydric stress. Thus, vineyard plots with a soil depth of 20 cm to 40 cm score best on this criterion. Vineyard plots with soils deeper than 50cm and/or vineyard plots with a soil binding coefficient of above 2 are ineligible.
GEOLOGICAL CRITERIA :
To ensure that wines have a strong identity from the land, only vines rooted in ancient bedrock formations are eligible. To limit vegetative outgrowth (foliage and wood), subsoils featuring fractured, crumbling or weathering bedrock are preferred.
Vineyard plots lying on silty sediment, or any Plio-Quaternary or Quarternary formations are ineligible for Cru Vallet status. Vineyard plots on ancient bedrock that is excessively weathered are also ineligible, as porosity becomes a limiting factor and leads to excessive vigour. Finally, any plots with very hydromorphic soil up to 60 cm deep are excluded from the Cru Vallet appellation.
A large family of rocks can be found within the Cru Vallet perimeter. Siliceous rocks, strongly dominated by micaschist, occur in the area, although some intrusions of gneiss and some inclusions of granite also occur.
However, since we are aware of the importance of having a final product with a common identity, our collective of winegrowers is today working on a clear definition for Cru Vallet wine, particularly in terms of its organoleptic characteristics.