y friends are always surprised when I tell them that I often visit winery tasting rooms. "But why?" they exclaim. "After all, you can get on the inside." That's true. And I do plenty of that, too. But sometimes you don't want "the treatment." You just want to be a regular wine sort and waltz into a tasting room to experience wines and wineries like everyone else.

Also, sometimes you want to take the measure of a winery new to you without committing a lot of time. Believe me, nothing is more painful than a private visit to a winery whose wines, you belatedly discover, aren't for you.

On the other hand, one of wine's greatest thrills is happening upon a winery about which you know nothing and discovering an unknown (to you) gem. That recently occurred in, of all places, Napa Valley.

I was working the Silverado Trail on the east side of Napa Valley and spotted a sign for a place I've passed dozens of times but never bothered to visit: Casa Nuestra Winery.

So, I stopped and found myself in a tiny, funky tasting room. Casa Nuestra, I discovered, has been around since 1979. All right, so I'm a little late.

I soon discovered that Casa Nuestra is much smaller than your average Napa Valley winery, what with a total annual production of just 1,500 cases divided among seven wines. Even by Burgundy's standards that's fractionalized, never mind in Napa Valley, where "small" means 15,000 cases a year.

The first wine offered was a 2001 Chenin Blanc. I groaned inwardly, because too many California Chenin Blancs are dullards. Boy, was I ever surprised. This was terrific Chenin Blanc: dry, not a trace of oak and suffused with the grape's signature scent of anise/licorice. The vines are 40 years old. The bottle price? $16. I bought two cases.

Then came another mindblower, a red wine called Tinto Classico from the 2000 vintage. "It's made from nine different grape varieties: Petite Sirah, Zinfandel, Alicante Bouscher, Carignane, Mondeuse, Gamay Mourvèdre, Cabernet Pfeffer and Pinot Noir," said my tasting room server, who was the entire tasting room staff that day.

Now, I have to tell you that I usually find such "field blends" to be less than inspiring. Wrong again. It had a strong whiff of peppery Pitite Sirah with a note of dried cherries, probably from the Zinfandel and Pinot Noir. "It's from a 60-year old vineyard in Oakville," the server noted.

With that, I felt like I had gone down the rabbit hole. There's a 60-year old vineyard in Oakville–land of $100 Cabernets–with a field blend? "Actually, it's right next to Harlan Estate," she said. "We had to raise the price a bit," she added apologetically. "It's $30."

This is the kind of tasting room experience I adore. It's the thrill of discovery, that unmatched sensation of having been there before the word got out. That seems impossible these days, but clearly it's not."