Dunne on Wine

Dunne on wine: Vintners in pursuit of zin mastery

Just as I start to look for answers to the most crucial questions – Where should I plant my vineyard? How am I to pay for it? – I learn I also need to decide what kind of zinfandel I’m to grow.

That’s the problem with spending only a few hours at UC Davis: Education can raise as many questions as it answers.

But first, why do I even ask what kind of zinfandel to plant? There’s just one, right? Well, yes and no. Basically, zinfandel is a black grape known today in California simply as zinfandel. It’s long gone by several other names, however: crljenak kastelanski, tribidrag, primitivo and, my favorite, Black St. Peters.

That mixed nomenclature aside, zinfandel has evolved and fragmented into scores of different strains, which within wine circles are called “clones.”

The wide range of zinfandel’s mutations became apparent to UC Davis researchers in 1995 as they began to collect budwood from about 50 old zinfandel vineyards in 14 counties about the state. With this material the scientists established what initially was a 1-acre vineyard at the university’s Oakville Research Station in the middle of Napa Valley.

Today, this “Zinfandel Heritage Vineyard” has grown to 21/2 acres with 22 of the selected vines. (Scientists found that several selections either were diseased or duplicates, thus the cutback.)

Though zinfandel has produced fine wine in California since the Gold Rush, it hasn’t garnered the acclaim given several other varieties, such as cabernet sauvignon and pinot noir. Thus, growers and winemakers hoping to pinpoint strains of zinfandel that might ultimately raise the grape’s stature have agitated for this research. Toward that end, Zinfandel Advocates & Producers (ZAP), a trade and consumer group, has spent $410,000 underwriting the study.

“How do we make it even better so it is recognized for what it is?” muses longtime California zinfandel specialist Joel Peterson in explaining the rationale for the research, of which he’s been a leader since its inception.

In hopes of getting a handle on how the research is progressing, UC Davis and ZAP officials this fall staged a blind tasting of wines made from eight promising strains of zinfandel being nurtured in the Napa Valley test plot.

The 40 participants who gathered in the sensory lab of the Robert Mondavi Institute for Wine and Food Science on the Davis campus were told only that the wines were from the heritage vineyard and had been grown identically, had been harvested at the same time in 2012, and were fermented, filtered and bottled alike, without aging in oak barrels.

The wines were identified only by a code, not their clone number. The name of the vineyards that provided the original budwood is being kept confidential in part at the request of some growers and in part so the study can proceed without bias. University officials acknowledged, however, that several clones are from high-profile vineyards recognized for yielding consistently some of the state’s more respected zinfandels.

As a group, the wines were brightly colored, fresh and fruity in aroma, and frisky with zinfandel’s telltale red-berry flavors. By and large, differences were more slight than dramatic. A couple were spicier than others, a couple were leaner in structure, and a couple were longer in the finish, but overall the family resemblance was clear through the lineup.

When a vote was taken, a couple of surprises developed. The overall favorite was the first wine in the lineup, notably denser in color and more lush in fruit than the others. This wine, it turned out, was the only primitivo in the tasting, made with grapes from one of the garden’s two clones from the Italian region of Puglia. (Zinfandel and primitivo share identical DNA.)

Peterson was quick to note that the primitivo likely stood out because it’s a strain that matures fairly early compared with the rest of the field, thus yielding a wine with more color, higher alcohol and riper flavor.

The wine that finished a close second, however, also was a surprise. It was made from the often-maligned “Clone 30” strain of zinfandel, sometimes called the “UC Davis clone” or the “white zinfandel” clone, given its reputation for productivity and adaptability. The wine it produced for the tasting was sleek, crisp and readily accessible; it was absolutely inoffensive, but didn’t say “zinfandel” with a whole lot of conviction.

On the other hand, the wine made from what turned out to be Clone 79 was to my palate the most expressive representative of zinfandel in the room. It had classic zinfandel flavor – all raspberry and blackberry with a dash of spice. It was fresh, lean and balanced in the claret mold, but it finished with uncommon lushness, complexity and persistence. In the vote, however, it ranked only in the middle of the pack.

The cuttings that produced the Clone 79 wine originated with an undisclosed vineyard in San Luis Obispo County. That’s where I’d head to continue my sleuthing for the material with which to establish my vineyard.

At least that’s what I was thinking until UC Davis grape breeder Andrew Walker spoke at the end of the tasting. He talked of how the heritage vineyard is helping researchers understand how such factors as the number of grapes per cluster, the size of berries and the tannin of seeds affect the nature of wine.

So far, however, the study has found little genetic difference in how the vines look and behave and how the wines they produce taste. Much more remains to be learned. The ZAP-sponsored study, for one, is just entering its third phase, which involves taking some of the promising strains of zinfandel from Oakville and planting them on sites about the state.

But for now, says Walker, environmental factors look to be trumping clonal differences in determining how zinfandel expresses itself. I’m still nuts about Clone 79 and look forward to seeing how it shows elsewhere.