The Topography of Chile’s Coast (Image from the Wines of Chile)
As we discovered last time, the Humboldt Current generates a river of cold water that profoundly impacts the Chile’s coastal climate. This cold water current cools the air over the sea, leading to a classic thermal inversion during the summer months. This inversion causes the condensed humidity from the day to form a thick fog that blankets the sea and coast. This fog is reminiscent of the mist famously seen in California’s Sonoma Coast and the Santa Lucía Highlands, but on a larger scale. This fog also filters sunlight, which affects grape varieties with short ripening cycles, such as Chardonnay, Sauvignon Blanc, and Pinot Noir. Consequently, these varieties develop slowly and delicately under the foggy conditions.
In addition, this effect of the Humboldt Current defines the daytime temperatures along the coast. Temperatures remain low along the ocean and the coast before rising sharply further inland to match the topography of the inner valleys. By thirty-five miles inland, the effects have completely disappeared.
The topography also plays an important role. In central Chile an ancient mountain range known as the Cordillera de la Costa (the Coastal Range) runs parallel to the ocean along a 2,000- mile stretch. This range acts as a barrier to the influence of the Humboldt Current. On the western slopes, the effects of the Humboldt Curren can be felt, while the eastern side is affected less the further it is from the sea.
The combination of granite soils and a consistent climate make for a terroir of a kind not found anywhere else in the world, where vineyards are planted along a 600-mile long stretch. Within this 20- to 30-mile wide strip, where the granite is combined with clay or sandy loam depending on the area, temperatures and sunlight are quite consistent. Without the Humboldt Current, the climate would vary widely by latitude and topography.
The main coastal terroirs of Chile are, running from south to north: Itata, Colchagua Costa, Leyda & San Antonio, Casablanca, Limarí and Huasco.
Next time well take a look at the Humboldt Current’s imprint on the wines of Chile. Cheers!