This is a "ghost winery," a term given to wineries started in the mid-to-late 19th century, a time when the California wine industry was booming. Most were abandoned early in the 20th century, victims of phylloxera, Prohibition and the Great Depression, and thus became "ghosts."
A few have been rescued and renovated. Regusci, whose tasting room is in a building constructed in 1878 by California wine pioneer Terrill Grigsby, is an example of a fantastically preserved ghost winery.