Why is California Pinot Noir often planted along the coast?
In California, a state famous for sunshine and beach weather, the pinot noir grape finds its preferred temperature envelope on the cool coast.
In concert with the moist air blowing in from the ocean, “upwelling”—the process by which the California Current brings cold, deep water to the surface—creates the heavy marine layer that blankets our coastline for much of the summer. The fog’s inroads onshore vary according to the character of the coastline. You can see this in the below map.
The Santa Lucia Highlands
Our small appellation is situated on the hillsides of this coastal mountain range, which descends to meet the large basin of Monterey Bay. The Gabilan formation rises opposite and in parallel. Together with the Bay, the twin ranges pull the moist air through the intervening lowlands. The combination of basin and range acts as a funnel for the fog. And a thick fog it is, as you can see from the images we have provided below.
The direct path that exists between the Pacific Ocean and the Santa Lucia highlands encourages the marine layer to creep well inland.
In our valley, the fog layer begins to form in the evening and rolls across the land by nightfall. After chilling the vines into the early morning hours, the fog layer gently begins to recede—typically, by late morning. Below are photographs taken above the Santa Lucia Highlands: One in the early morning, and another when the fog is beginning to break up over two of the areas we farm: the Garys’ and Soberanes Vineyards.
When this advection fog is in place—essentially every day of the summer—it creates what looks like a wool blanket over the valley and the highlands. Under this blanket rest the grapevines, cooled, and slowly ripening.
One of the ironies about grape growing in our area is that the cold weather the vines thrive upon has also made the Salinas Valley famous for vegetable production. The majority of the lettuce consumed in the U.S. is produced here. Like grapes, lettuce production thrives on foggy weather (although it is important to note that each is grown in extremely different soils).
Why is fog beneficial for pinot noir?
Pinot noir is famous for its complex, vibrant aromatics. Growing this wine in long, cool seasons enriches and deepens its concentration of aromatic compounds (Watson, et al 1991). The foggy climate also encourages the retention of acid in the wine (Winkler, 1974), which helps produce the beautiful vibrancy for which this wine is so justly celebrated.
Like anything positive, however, the fog has its challenges. Botrytis caused from moisture is a common and notorious difficulty. In the early morning, condensation often literally drips from the vines, raising the possibility of mildew.
Fortunately, when the fog recedes, it is replaced by whipping winds that rush down the valley. These scouring breezes help to dry out the vines. The air movement also helps to maintain cool temperatures despite the sunshine. We will provide more discussion of this balance between moisture and sunshine in a later posting.