The Martikov Family line has been the keeper of The Wizard of Wines Winery for the past 600 hundred years, after marrying into and subsuming the branch house of the Krezkov line that had originally owned it. The winery itself, however, predates even Strahd's entrance to the valley.
It is said that a powerful wizard was the original owner and creator of the winery and planted the original vineyards. He created three magical gems that, when planted in the soil, help produce the three breeds of healthy grapevines. These gems are what allow this otherwise cold ground to produce plump grapes that are turned into delectable wine for the entire valley to enjoy.