Most of the vineyards in Santorini are found in the southern and southwestern part of the island, on soil of volcanic origin (Therean ash and pumice) and sandy composition, with virtually zero moisture capacity and organic matter -which explains the absence of phylloxera. White varieties hold sway in the vineyards of Santorini, with Assyrtiko being the most prominent cultivar on 1,700 acres and the aromatic Aidani coming a close second. Santorini enjoys an ideal Mediterranean climate with mild winters and warm, dry summers. Rainfall is very low, and the little rain that falls on Santorini falls mostly in the winter. However, the porous soils of the island help retain humidity from dew, rainfall, and moisture from the sea, ensuring an adequate water supply for the vines during the growing season. As a result, Santorini’s unique ecosystem is a harmonious climate for its native grape, Assyrtiko. The grape has perfectly adapted to the local conditions and remains hearty during the warm, dry summers of Santorini.
The summer heat is made bearable by strong winds and cool sea breezes. This island in the middle of the Aegean sea is buffeted by winds from every direction which can pose a real threat to the vines. They are a threat to the vines not only because they bring the salt from the sea air and the sand from as far away as the North-African coast, but primarily because of their sheer strength. They have been known to blow down trellised vineyards in a matter of minutes. However, the dominant wind—known as Meltemi, a real danger to sailors—is actually quite beneficial for the vine. This cool wind blows from the north mostly during the growing season. The Meltemi is an integral part of Santorini’s unique ecosystem, helping to lower temperatures and allowing for slower ripening of the grapes. Island’s vintners train the vine stocks into traditional wreath-like baskets (known as “kouloura,” or “ambelia”) in order to shelter the grapes from the wind and direct exposure to sunlight.
The winds are also very beneficial in keeping typical vineyard scourges at bay. The constant circulation of air wards off rot and disease – keeping the vines healthy and protected. As a result, the winds, in combination with the low rainfall and volcanic soils, contribute to Santorini’s unique ecosystem.
The extremely low yields of Santorini high quality wines are a natural result of the old vines, the volcanic soils, the hydric stress and the strong winds of Santorini’s unique ecosystem. They all contribute to the concentration and the richness of its wines. Indeed, the law allows yields of up to 55 hl/ha, but these are rarely, if ever, reached. An abundant harvest could turn in close to 40 hl/ha, but normal yields are closer to 20 hl/ha, often even dipping below 10 hl/ha.