From the Expert Guide:"Napa Valley forbids the cultivation of any slope greater than 30 degrees, which also limits vineyard size. That said, a handful of even steeper sites that were planted before this ordinance have been grandfathered in and can still be spotted among Napa’s many hillsides."
Anyone know what these grandfathered steep vineyards are? Reading it got my curiosity up when I couldn't name any off the top of my head.
Hi! Yes - there are several. That super steep parts of Bacchus and of Steltzner, I'm pretty sure, are over 30 degrees. Also I think parts of Cain and Burgess qualify as well. I know that there are more I'm not thinking of, but in general I believe it is more about portions of established vineyards being grandfathered in, rather than an entire vineyard, per se.
On the Sonoma side ( I believe the slope imitations are the same) there's Martinelli's Jackass Hill and the Hidden Ridge / Immortal Estate up in the Mayacamas