California wine is wine made in the U.S. state of California. Almost three quarters the size of France, California accounts for nearly 90 percent of American wine production. The production of wine in California alone is one third larger than that of Australia. If California were a separate country, it would be the world's fourth largest wine producer. The state's viticultural history dates back to the 18th century when Spanish missionaries planted the first vineyards to produce wine for Mass.