 The calcareous subsoils are porous which helps to retain some of the humidity in the air and release it as moisture in the night for the vines to utilize.The island of Santorini is most famously known for its indigenous white grape varieties Assyrtiko, Athiri and Aidani, though some wines made from international varieties and also from indigenous red grapes such as Mandalieria and Mavrotragano can be found.About 1,200 hectares of land are under vine, however, there is a constant struggle with Santorini's tourism industry that puts this small number at risk of decreasing even further.