We went to Hagafen a number of years ago and the people there were delightful. We called first to confirm that they were open, and to get directions, and to our very pleasant surprise the owner (or possibly his father) was waiting near the entrance because the sign was obscured (or something) so he helped show us in. They could not have been more warm and courteous.
Just found this thread with a Google search for "kosher napa wine". Not to revive an old topic, but a quick message to internet users of the future:
There are two Napa wineries offering Kosher wine:
Hagafen Cellars - hagafen.com
and Covenant Wines - covenantwines.com
You can read about the difference between tasting room experiences in this blog post I found: Rick's Wine Country Journal. http://winecountry.blueherontours.com...
There's only 1, and that's Hagafen. We used to be in the neighboring county of Sonoma, but we sold and relocated to LA for the education of the kids. There's another small winery a couple of hours away in the Santa Cruz mountains, Four Gates. Finally, if you're coming down to the LA area, you can check out Herzog in Oxnard. Sorry, but California doesn't really have much in the way of kosher winery faclities.