You think two buck chuck is made from grapes grown in ritzy Napa valley? Large majority of California wine comes from grapes grown in the central valley.

* The Central Valley is California's largest wine region stretching for 300 miles (480 km) from the Sacramento Valley south to the San Joaquin Valley. This one region produces nearly 75% of all California wine grapes and includes many of California's bulk, box and jug wine producers like Gallo, Franzia and Bronco Wine Company.*

https://en.wikipedia.org/wiki/California_wine#Wine_regions