By Robert Haas
In the early 1970’s Jean-Pierre Perrin accompanied me when I was visiting my then Napa Valley suppliers of Vineyard Brands: Freemark Abbey, Chappellet, Clos du Val and Phelps. We took a little tour of the valley and he remarked that it was extraordinary that, in a climate that seemed extremely apt, there were none of the grape varieties traditional to the Rhône. It was this experience that was the beginning of the idea of doing it ourselves. However, we were pretty busy developing our own businesses at the time and the idea, never forgotten, got shelved for a while.
In 1985, we decided to give it a try and began seeking a proper location. We were looking for three things: a Mediterranean climate similar to that of the southern Rhône, enough annual rainfall to grow grapes without having to irrigate regularly, and maybe most importantly – certainly most restrictively – calcareous (chalky) clay soils similar to those of Beaucastel.
As we had noted in the 1970’s, much of coastal California has a classic Mediterranean climate. But more specifically, we wanted an area with both a long growing season to ripen late-ripening grapes like Mourvèdre and Roussanne and moderating influence (like elevation, nighttime cooling or fog) that could keep the earlier ripening Rhone varieties like Syrah and Viognier from becoming heavy and flabby. Paso Robles has the largest day-night swing in temperature of any wine growing region in North America, typically 45 degrees and often more. (This week, we’ve had several days with 55 degree swings: daytime highs over 100 and nighttime lows in the 40’s!) The proximity of the cold Pacific Ocean, which never gets much above 60 degrees even in mid-summer, and the dry summer climate that allows the day’s heat to radiate off at night provide cooling, while the relatively unbroken 3000-foot high Santa Lucia mountains protect the region during the daytime and allow it to warm up.
Even better, the further south you go in California, the later the onset of the winter rainy season. We typically get our first serious winter rainstorm in the middle of November, two weeks later than our colleagues in Napa and a month later than those in Sonoma. The extra weeks matter in cool years, and we have harvested into November five of the last seven vintages.
The lower limit for dry-farming grapevines is about 25 inches of rain annually. We get that much here thanks to our 1500-foot elevation and our location in the Santa Lucia foothills just 11 miles from the Pacific. Pacific storms are pushed up into cooler air as they cross over the mountains. This cooler air can carry less moisture, so the clouds drop it as rainfall. Our average rainfall of about 28 inches is double what the town of Paso Robles receives just ten miles further east and 800 feet lower. We figure we’re just about the most southerly location in California (and one of the warmest) to receive this much rainfall.
Finally, and we thought most importantly, we felt that chalky soils would give us, as they do in the southern Rhône Valley, healthier vines with better water retention, better nutrient availability, healthier root system development and more disease resistance (for a full discussion of the qualities of chalky soils, see the 2010 blog post Why Limestone Matters for Grape Growing). We found our spot after four years of searching: 120 acres of rugged hilly terrain in the foothills of the Santa Lucia mountains. We bought it and that was the birth of Tablas Creek Vineyard.
But why are there chalky soils here? The story begins sixty-five million years ago, toward the end of the Cretaceous period, when the fearsome Tyrannosaurus Rex ranged the land. At that time, the continental United States was largely covered by shallow seas, with only the Appalachian and Rocky Mountain ranges on dry land. What are now the central plains and the southeast, and both the east and west coasts (including what is now Paso Robles) were under the ocean. A map from the USGS shows it well:
The Pacific plate was then, as now, moving east and colliding with the North American plate, pushing up the land that now forms the western shore of the North American continent. (A fascinating series of maps on the Paleogeography and Geologic Evolution of North America can be found at https://deeptimemaps.com/global-paleogeography-and-tectonics-in-deep-time/)
The Cretaceous period, starting about one hundred forty million years ago and ending sixty-five million years ago, was the earth’s most active period of chalk formation. Chalk is principally calcium carbonate. The circulation of seawater through mid-ocean sea ridges during the Cretaceous – a time when mid-ocean ridges were unusually active – made Cretaceous oceans particularly rich in calcium. This richness stimulated the growth of calcareous nanoplankton, the tiny sea creatures whose calcium-rich skeletons settle to the sea floor and eventually accumulate to form chalk and its metamorphic relations limestone and marble. It was during the Cretaceous that the chalk cliffs of Dover and the chalky hillsides of Champagne and the Loire were formed; as were the chalky clay soils around Tablas Creek in west Paso Robles.
The seas began to recede toward the end of the Cretaceous and continued through the Tertiary, driven initially by the slower growth of mid-sea ridges and a cooler climate that would eventually trap large quantities of water in glaciers. The sedimentary chalk-rich rocks that had been laid down in the Cretaceous were exposed throughout the middle portions of the United States. In California, seismic activity pushed up calcareous soils in only a few places, principally along the Santa Lucia Mountain range, where these soils were folded and intermixed with older continental and volcanic soils. Much of these soils are west of the coastal range, in climates too cool to ripen Rhone varieties. It was our good fortune that one large exposed chalky layer was east of the coastal range, in west Paso Robles and Templeton.
So, all three components come together here in Paso Robles. Chalky soils sit at the surface. We typically get enough rain to farm without having to irrigate. And it warms up enough to grow the grapes we love, while staying moderated enough to keep them in balance.