SONOITA -- , Ariz. - Todd Bostock calls it his wall of humility. At his Dos Cabezas Wineworks, in this remote crossroads 23 miles north of the Mexican border, barrels keep company with shelves full of some of the world's great bottles - empties.

Of note are those from Marcel Deiss, the Alsace house known for field blends that often combine white and red grapes, in the belief that a great site's qualities matter most.

A dose of Deissian inspiration helps to explain Bostock's nearby 15-acre Pronghorn vineyard in the town of Elgin.

Foremost, there's Tempranillo planted, but it's mixed with at least 10 varieties, everything from Petite Sirah to Roussanne, Marsanne and Viognier, all growing at 4,800 feet, with high prairie and the domed peaks of the Santa Rita range in the distance.

The whole lot is thrown together to become Dos Cabezas' heady, fragrant red El Campo. It offers, for better or worse, a sense of Sonoita.

"That's what's so exciting about making wine here," says Bostock, 36, who runs the winery with his wife, Kelly. "No one knows what the region tastes like yet."

True enough. Located in Santa Cruz County, Arizona's smallest, Sonoita blends Western grit - its rodeo has been going for 98 years - with the presence of the bordering Mexican state of Sonora. The Border Patrol maintains a major detachment here.

It is also the touchstone of Arizona wine. The state's first modern wine grapes were grown nearby, and 208,000 acres surrounding Sonoita were designated a federal appellation in 1984.

With 60 bonded wineries, Arizona's industry is still in its infancy after more than three decades. It has occasionally had overachievers, like Callaghan Vineyards just down the road from Bostock's vines. But recent years have witnessed a newfound seriousness to viticulture, and an influx of winemaking talent. Arizona is poised to blossom beyond regional status - to become, as Washington and Virginia did, part of the national conversation.

That progress is guided by vintners like the Bostocks, whose El Campo became, last year, the first Arizona wine ever to make The Chronicle's Top 100.

A Phoenix native whose parents who didn't drink, Todd Bostock began making homemade wine while running a print shop in Portland, Ore. After returning home, he began helping at Dos Cabezas in 2002, then purchased the winery in 2006.

Farming in Sonoita is an exercise in adaptation. Each vine cordon at Pronghorn hovers nearly 4 feet off the ground, "to get it up out of the heat and into the wind when it rains."

Rainy days

And boy, does it rain. This corner of Arizona, 50 miles southeast of Tucson, is swamped each summer by monsoons that dump up to 14 inches, enough to make a Bordelais buy an umbrella. Snow can come as late as May. Yet water is a concern much of the year.

But Bostock and neighbors like Kent Callaghan, whose family opened their winery in 1990, are persevering. Bostock even drags a movable chicken coop through his vines to amend poor soil that's as alkaline as baking soda. He stopped spreading grape pomace when it hardened into a cake in the arid offseason.

"It seems counterproductive to irrigate your compost," he says.

The altitude, however, brings comparatively mild temperatures to Sonoita's grasslands, even as Tucson bakes in the Sonoran desert below.

"You look at Napa, Paso Robles and Dundee," Kent Callaghan tells me, referring to key California and Oregon wine areas, "and they're all hotter than we are." This depends which data you consider, but certainly mean temperatures are similar to Napa's.

Sonoita also has remarkable geology - a mix of red clay and the white clay known as caliche, which largely consists of the calcium so elusive in California soils, interspersed with fossils and seashells. It is a reminder that much of Arizona was once an inland sea.

The geology prompted soil scientist Gordon Dutt and A. Blake Brophy to plant the state's first vineyard in Elgin in the early 1970s, and Dutt - considered the father of Arizona wine - to set up his own winery in Sonoita.

But by no means is it Arizona's only wine country. Due east, in Cochise County, a robust industry has grown around the town of Willcox. Its deeper, loamier soils are the source for most of the state's wine grapes, and the site of such properties as Pillsbury Wine Co., owned by film director Sam Pillsbury, and Arizona Stronghold, which occupies the site of the original Dos Cabezas property.

The ownership, and the geography, of Arizona wineries can be tangled. Wines are often made nowhere near their source. Indeed, many of Bostock's and Callaghan's wines come from Cochise vineyards. Sonoita's stingy yields - 2 tons per acre in a good year - could never provide Dos Cabezas with enough grapes for its 6,500-case annual production.

In 2005, Dick Erath, one of Oregon's wine pioneers, bought 40 acres in Willcox to plant his Cimarron vineyard. After installing vines in the backyard of his Tucson winter home, Erath had looked east, entranced by the complex, calcium-rich soils.

Thick skins

What he found is what plagues most aspiring wine regions: vineyards full of familiar grapes like Chardonnay that, not surprisingly, were horrid matches for Arizona. "They planted Pinot Gris," Erath recalls, "which looked like it wanted to crawl underneath the ground."

What, then, should Arizona grow? Given the southerly latitude, Erath gravitated to thicker-skinned varieties indigenous to southern Europe, like Aglianico and Mourvedre. Cimarron now contains Tempranillo and Primitivo, along with a large roster of Rhone natives like Picpoul. He concluded that most did better when blended.

"When the dust settles, I wouldn't be surprised if there are a dozen red varieties that do well," says Erath, who sold Cimarron to Bostock in 2011.

Tempranillo seems to have a particular affinity for the soils. In Sonoita, especially, the grape displays a freshness to its tannins discernible in great Spanish versions but often lacking elsewhere.

It can be tasted in a wine like Dos Cabezas' Aquileon, where it's combined with Graciano (Rioja's other significant grape) and Mourvedre. Mourvedre, too, shines, in reds like the Callaghan Claire's.

Great white hope

The other, improbable standout is Malvasia Bianca. Young vintners are crafting versions that display the depth of the best Italian whites - people like Rob and Sarah Hammelman, who make one for their Sand-Reckoner label in Willcox along with several red blends.

The grape thrives not only in Cochise, but also five hours north, in the Verde Valley.

If southern Arizona's vineyards are mostly found off roads leading to not much of anywhere, Verde Valley enjoys its proximity to the resort town of Sedona, which sits at its northern edge.

Here, too, the right grapes are slowly being routed to the right spots - a task that has kept Maynard Keenan, of Caduceus Cellars and Merkin Vineyards, busy since 2002, when he first planted in his adopted hometown of Jerome, an old mining center 5,200 feet high above the scrubland.

Yavapai County, in which Verde Valley is located, has perhaps 150 acres in vine. But it has given Keenan and others like Eric Glomski, who founded nearby Page Springs Cellars, a useful laboratory.

After a UC Davis adviser suggested planting Cabernet, which was promptly wiped out by Pierce's disease, Keenan took the opportunity to plant more intriguing choices - Italian grapes like Nebbiolo and Aglianico, plus everything from Tempranillo to Malvasia, starting with the steep terraces of his 1 1/2-acre home vineyard.

"You really have to cover the fruit, because the sun will just fry it," Keenan tells me as we look at the spindly vines' relatively bushy leaf cover. "Those little dumb differences between here and Napa are what we've had to figure out."

Like Sonoita, Jerome sits atop a massive limestone bed, along with a major copper vein. The soils are a mix of caliche and old volcanic material. But Keenan has planted throughout the county: 20 varieties across 38 acres, including parcels in nearby Cornville, home to one Sen. John McCain. Nerello Mascalese, native to Sicily's Mount Etna, is on his to-do list.

Keenan's success has another component, of course. As the singer in the band Tool, his rock-star status gave Caduceus both visibility - it was the subject of the 2010 documentary "Blood Into Wine" - and the specter of a celebrity vintner cooling heels.

But Keenan, who grew up in rural Michigan, bristled at that last part. When he finally finished his facility in 2009, and having trained alongside winemakers like Arizona Stronghold's Tim White, he decided he would make the wine himself.

"I realized this is 'dive in the deep end,' " he says. "What's the worst that could happen? I'm no good at it, and I hire someone."

High expectations

Hence the other key to Arizona's ascent: a handful of winemakers who not only demand good farming, but operate with California-level expectations.

Glomski is a veteran of David Bruce Winery in Los Gatos, while Rob Hammelman worked for the Saint-Cosme estate in the Rhone. Bostock's cellar contains avant-garde amenities typically found closer to the coast, down to its concrete fermentation eggs.

That has sparked what Pavle Milic, co-owner of FnB restaurant in Scottsdale, describes as a breakaway contingent: a half-dozen vintners whose wines can compete farther afield.

"I think there's a good group of people who care about posterity," he says.

While local wines rarely cross state borders, that is in part because they have resonated with a current generation of Arizona chefs dedicated to promoting local food, courting farmers and nurturing organic vegetable gardens through the summer heat.

Shortly after opening FnB in 2009, Milic, who had worked at restaurateur Peter Kasperski's Cowboy Ciao, decided that his wine list should mirror chef Charleen Badman's local focus. Having been away for three years in Napa Valley, Milic was impressed by the quantum leap in Arizona wine quality. He now collaborates with Dos Cabezas on wine for the restaurant.

Chef Greg LaPrad, whose restaurant Quiessence was an anchor of Phoenix's farm-to-table movement, took that even further when he moved to Sonoita earlier this year. This fall, he will open Overland Trout, with a menu that attempts to elevate local bounty, everything from black beans to nopales, and even Sonoran white wheat, which was revived with help from Gary Nabhan, a key figure in the seed-saving movement, who lives nearby.

There's still work ahead. A raft of generally bad advice from California left Arizona viticulture hobbled for many years. In Verde Valley, Keenan is building a co-op winery as an incubator for cash-poor winemakers, and assisting the local community college, which recently launched Arizona's first viticulture and enology program.

Crucially, the belief has spread that Arizona wine won't succeed until it hones an identity. Bostock's El Campo is a vital step toward defining one.

"We're not a cover band. We're not trying to emulate someone else," he says. "We're trying to be our own original thing."