 The grapes are also sun dried, but before vinification dry grape must is added to the run-off juice from the raisoned grapes.Vinsanto is an ancient winemaking tradition of Santorini that dates back thousands of years and represents an important part of Santorini's history.In order for a wine to be labeled Vinsanto in Santorini the wine must be predominately made from the Assyrtiko grape—at least 51%, the remaining 49% is made up of Athiri and Aidani and some small amounts of locally grown white varieties.