Drive inland from the Pacific on Highway 46 and the light changes. The fog burns off, the hills turn the color of a lion’s coat, and rows of gnarled Zinfandel give way to Syrah, Grenache, and Cabernet planted on chalk-white limestone.

This is Paso Robles, the sprawling, sun-soaked center of California’s Central Coast. Halfway between Los Angeles and San Francisco, it is the largest wine appellation in the state and, over the last thirty years, one of the fastest rising. The wines are generous and warm-hearted, built on big diurnal swings and ancient seabed soils, and the welcome is the opposite of stuffy. Paso is where serious winemaking met a frontier sense of freedom, and the result is a region that does Rhône blends, Cabernet, and Zinfandel with equal conviction.

From mission vines to a Rhône revolution

Wine has grown here since the Franciscan padres founded Mission San Miguel Arcángel in 1797 and planted the first vineyards a few miles north of present-day Paso Robles. Commercial winemaking began in 1882, when Andrew York established the Ascension Winery, later York Mountain, and introduced Zinfandel to the hills west of town. In 1914 the Polish pianist and statesman Ignacy Jan Paderewski bought a ranch on the Adelaida slopes and planted Zinfandel and Petite Sirah, sending his fruit to wines that won medals before Prohibition closed the cellars.

For most of the twentieth century Paso stayed a place of dry-farmed Zinfandel, almond orchards, and cattle. The turn came in 1989, when importer Robert Haas and the Perrin family of Château de Beaucastel in Châteauneuf-du-Pape went looking for the closest thing in America to the limestone soils of the southern Rhône. They found it on the west side of Paso and founded Tablas Creek, importing cuttings of Mourvèdre, Grenache, Syrah, and Roussanne directly from Beaucastel. Those vines, and the nursery Tablas built around them, seeded a Rhône movement that now defines the region.

The Rhône Rangers had found their California home, and the wine world was about to notice.

By the late 1990s it had. Justin Baldwin, who founded Justin Vineyards in 1981, saw his Bordeaux-style Isosceles named one of the top wines on earth. Stephan Asseo left a winemaking family in Bordeaux for the freedom of Paso and built L’Aventure into a cult name. Justin Smith’s Saxum, from his family’s James Berry Vineyard, earned a 100-point reputation and Wine Spectator’s Wine of the Year for the 2007 vintage. Today more than two hundred wineries work these hills, and the Daou brothers’ mountain Cabernets draw comparisons to Napa at a fraction of the price.

The widest temperature swing in California

Paso Robles owns the largest day-to-night temperature swing of any appellation in the state. Summer afternoons climb past 100 degrees, then ocean air slips through the Templeton Gap, a low break in the Santa Lucia Range, and drops the temperature 40 to 50 degrees by dawn. Grapes ripen fully in the heat but hold their acid in the cold, and that tension is the secret behind Paso’s combination of power and freshness.

Underfoot, the west side is built on calcareous limestone and fossilized seabed, the same chalky, alkaline soil that runs beneath Châteauneuf-du-Pape and parts of Burgundy. It stresses the vine, holds a little water through the dry summer, and gives the wines a mineral spine. The AVA itself is enormous, more than 600,000 acres with around 32,000 planted to vine, climbing from 700 feet on the valley floor to 2,400 feet in the western hills. That scale is exactly why, in 2014, growers divided Paso into eleven distinct sub-appellations.

Zinfandel heritage, Cabernet crown, Rhône soul

Three threads run through every great Paso cellar. Zinfandel is the heritage grape, planted in the 1880s and still made from old dry-farmed vines that taste of brambleberry and sun-warmed earth. Cabernet Sauvignon is now the most planted variety and the region’s commercial engine, ripe and generous, with the mountain sites turning out serious, age-worthy bottles. And the Rhône varieties, led by Syrah, Grenache, and Mourvèdre, are Paso’s soul, blended into the GSM reds and rich whites that first made critics look west. If you want one wine that says Paso, it is a warm, structured Rhône blend grown on limestone.