On the back of the recommendation, also check out this vineyard
http://www.brownestate.com/
You have to join (for free) in advanced if you want to buy anything first but when i was last in SF, I enjoyed the finest bottle of Zinfandel I have even experienced from this place.
Unfortunately, you can only buy their wines direct or from a handful of small local retailers so I have been unable to get a bottle back to the UK.