all photos courtesy of Caitlin and Austin
FYI: I didn't spill my wine, I was testing out my new wine snob trick, rolling the glass to coat the sides and enhance the aroma.
I would suggest that you do a little investigative work first, most of the wineries are open from about 10-4, but some require appointments and others do not. Also, there is the tour question, personally I love a good tour but even I max out around 3 (I mean really, after awhile they aren't exactly covering new material are they? There is only so much about wine making that you can understand without a viticulture degree). Some places have three or four tours a day and others have a tour every hour, so check with the winery if you have your heart set on a tour. Ideally, I would go on a sparkling and a still tour, because who doesn't want to know how the bubbles get into the champagne (I know, I know, it's not actually champagne, but sparkling wine doesn't have the same ring). Tastings generally run about $15 and up, unless you can grab a local to bring along, or get a coupon, I found an app on my iPhone that had lots of 2 for 1 tasting coupons but I didn't actually end up using any of them so I have no idea how well they work. I know ones taste in wine is much like ones taste in comedy in that people can have vastly different preferences, so these are just a couple of my favorite wineries and why I like them, which may or may not be helpful to you but it might give you a starting point for your own trip or let you live vicariously. Fair warning though, I am not a picky wine drinker, I like just about anything (although after a few tastings I can swirl and sniff like a pro, or at least a proficient amateur) so I tend to judge wineries on the overall experience and not entirely on the quality of wine.
Mondavi
I read a book called the House of Mondavi and I became slightly obsessed with Mondavi (I have a habit of developing generally brief, yet intense interests in various things, right now I am riding out an elephant phase, they are FASCINATING). Mondavi is an iconic winery, and by that I mean the Robert Mondavi Winery, not to be confused with Charles Krug or CK Mondavi or Opus One or Woodbridge by Mondavi all which have a Mondavi family relationship in one way or another (read the book if you want to know more, it is quite dramatic, especially if you skim over the more business/financially oriented sections). Robert was a key player in making the California wine scene what it is today and I think it seems fitting to visit his winery. And, while I don't believe the wine has the reputation it once did, it is still pretty good.
Artesa
Artesa is an absolutely gorgeous winery, it is up on a hilltop, not tucked away on the valley floor like many, so you can see for miles. Miles and miles of grapes and rolling hills, it's lovely. You can do a tasting at the bar or buy a bottle of wine or a flute of sparkling wine and take it out onto the patio so you can enjoy the view. Artesa is one of those places where the setting outshines the wine for me, not that the wine is bad, but I would go for the view. I hear you can see to San Francisco on a clear day. Apparently it has never been clear enough when I have been there.
Cakebread Cellars
Flora Springs
Mumm Napa
Mumm is my favorite sparkling wine place in the valley, the setting is gorgeous and you can get a flight of wine so you can taste it side by side which is a bit unusual. In the past we have gone and gotten a bottle or two for the table and each have a glass (or two, but no more as we learned they have a two flute max) instead of doing a tasting, but I am not sure if they do that anymore. According the Mumm tour guide, they have the smallest bubbles, smaller than say, Chandon, the other makers of sparkling wine I have visited there. Now I have never done a taste test, nor do I know how one would measure the average bubble size in a bottle of bubbly but I do know that Mumm has bubbles that are quite lovely and they do actually seem smaller than some of the, shall we say, less costly ones I have tasted.
And these are only a few of the dozens of possibilities, drive around, stop in where ever strikes your fancy, you may find a gem, it's all part of the fun.