by Thom Elkjer, Wine Editor

Zinfandel’s more passionate adherents got some wind knocked out of them in 2002, when the premium wine grape they described as “America’s own” turned out to be European – and from a never-heard-of-it neighborhood to boot.

In the years leading up to this discovery, Zin fans had become increasingly creative in defense of their chosen vine. When a southern Italian grape called Primitivo turned out to be genetically almost identical to Zinfandel, some Zin fans came up with a “reverse immigration” theory: the American grape was so good, they said, that Italian-Americans must have exported it back home to their winemaking cousins. (As if Italy, with more than 2,000 indigenous grape varieties, needed another one.)

Now we know that both Zinfandel and Primitivo share the same ancestor, a grape native to the Dalmatian (Adriatic) coast of Croatia. It’s called Crljenik Kasteljanski ("tsurl-yen-ik kahs-tell-yahn-ski"), and while it’s no big deal in its homeland, it’s indisputably European in origin.

At first this was a come-down for Zinfandel advocates and producers (known by their acronym, ZAP). But, like Zin itself, you can’t keep a true fan down. “Zin may come from somewhere else, but it’s still the only premium grape variety whose worldwide reference point is California,” avers Grady Wann, winemaker at Quivira and a past president of ZAP. In other words, the standards for Cabernet Sauvignon and Pinot Noir were originally set in Bordeaux and Burgundy, respectively; the standard for Zin comes from our own Golden State.

But what is it that makes California the “reference point” for Zinfandel?

History has to top the list. Zin has been a part of California wine culture for 150 years. It slaked the thirst of gold miners in the 1850s, kept immigrant families in wine during Prohibition in the 1920s, and has played a major role in democratizing California wine since the 1980s. What’s more, some of the vineyards and vines planted in Zin’s early days are still producing today, so we can taste its living history in the glass.

(A word to the wise: not all “old vine Zins” are created equal, but the term means more now than ten years ago, when anyone with the merest excuse would put “old vines” on a Zinfandel label to lure the unsuspecting.)

Drinking pleasure comes in a close second in the race to explain Zin’s performance in California. Zinfandel happens to be a notoriously uneven ripener, which means a single bunch can contain grapes ranging from just past green to way past raisin. California offers enough dry, sunny days in early fall to ripen Zin more evenly than other places, so the resulting wine offers a plush flood of rich fruit flavors interlaced with the spicy complexity that comes from mature skins, seeds and stems. As Wann notes, “California Zinfandel hits a pleasure point on your palate like no other wine.”

Finally, there is a culinary reason that Zin stands tall in America’s No. 1 state for outdoor dining. In a nation where wine and food are all about gusto, this not-so-secret weapon can be described in a single word: Barbecue.