If it weren’t for the Templeton Gap and other dips in the Santa Lucia Range allowing cool marine air from the Pacific Ocean to flow in, California’s Paso Robles region would not be home to 168 wineries. Its climate would be too hot to grow fine grapes. And if it did not have such a wide swing between day and night temperatures, its wines would not be so well-balanced.

Yet Paso Robles, on the Central Coast halfway between San Francisco and Los Angeles and the third-largest wine appellation in the United States, remains a region waiting to be discovered. Jerry Lohr was one of the region’s earliest pioneers, planting his first grapes three decades ago; today, his winery produces consistently first-rate, polished wines. Most of the more recently established wineries are small and without national distribution, although their wines can be ordered directly through their websites.

While the region’s climate is generally temperate, it is still warm and thus more conducive to red grapes. About 75 percent of its production is red, and most are Zinfandel and Rhône- and Bordeaux-style wines.

During a recent visit to Paso Robles, my days and evenings were filled with tastings. Here are some of the wines I found most impressive and most expressive of the region.

Ancient Peaks Winery Oyster Ridge 2009 ($50) is a blend of Cabernet Sauvignon, Petite Sirah, Petit Verdot and Malbec from its vineyard named for the oyster fossils in its soil.

Caliza Companion 2010 ($48) is a forthright, well-balanced blend of Cabernet Sauvignon and Syrah.

Herman Story Wines’ On The Road Grenache 2010 presents all sorts of fruits and berries and explosive favors; its Nuts & Bolts Syrah 2010 is deep-flavored and intense (each $42).

Linne Calodo Cellars’ Rising Tide 2007 ($45) is a deep, dark, full-bodied Rhône blend.

Vortex Zinfandel 2010 ($38) from Peachy Canyon Winery blends a flavorful Zinfandel with Petite Sirah and Malbec.

Pomar Junction Vineyard and Winery’s Viognier ($25) is dry, minerally and aromatic.

Night Watch 2008 ($50) from Sextant Wines offers a savory, satiny blend of Zinfandel, Syrah, Petite Sirah and Tempranillo.

Silver Horse Winery’s Tempranillo 2010 ($38) is firm and inviting.

Steinbeck Vineyard & Winery produces Cabernet Sauvignon 2007 ($45) with rich, dark cherry fruit and a hint of pepper.