Even Bay seniors with decent memories may not realize that the Napa Valley was an agricultural region long before the first grape vine was ever sown. As evidence I submit Bale Grist Mill on Highway 29 three miles north of uber chic St. Helena. This water powered mill was built in 1846 for local farmers to grind their corn and wheat into meal or flour, and continued operating until the early 1900’s. It is now a State Historic Park and on weekends between your wine tastings, you can stop by and see it in actual operation. If you feel like walking off your latest Napa gourmet blowout, the Bothe trail is right nearby. Free.