They are divided by their maturity into Fine de Claire, Speciale de Claire and Pousse en Claire. The more mature the oyster, the meatier it is.

They are also mostly cultivated in MarennesOléron, France,

Consistent shape
A large quantity of flesh with an ivory coloured mantle
Agreeable marine odour
Finished flavour of claire oysters
A sweetness predominant over saltiness
Firm consistency
Long on the palate

On tasting, the special de claire is distinct from the fine de claire by a firmer texture to the flesh, the volume in the mouth and a remarkable balance of sweetness and salt.

These oysters are finished for several weeks in shallow clay ponds, namely "claire" where they acquire a quality which is clearly superior to those from the open sea.