In this Ancient Peaks Soil Series, we explore the unique diversity of soil types found at our estate Margarita Vineyard. Today we take a look at the volcanic soils of Margarita Vineyard, which are located along the southwest border of the vineyard, including our Block 32 Zinfandel.

While Santa Margarita Ranch straddles two active fault lines, earthquakes aren’t the only mighty forces of nature to have made their mark on this land. Deep in our geological past, volcanic activity was prevalent along this stretch of the Pacific coast—most notably resulting in the creation of the “nine sisters,” a chain of fantastical-looking peaks that define the San Luis Obispo skyline.

Ancient Origins

Known as “morros,” these peaks were formed from ancient volcanic plugs. The most famous of the nine sisters is Morro Rock, a massive monolith that juts skyward from the waters of Morro Bay. Morro Rock was formed around 23 million years ago from the plug of a long-extinct volcano. Black Mountain, Bishop Peak, Cerro San Luis and Islay Hill are among the other morros that follow a straight line from Morro Bay to Edna Valley, passing just miles from Santa Margarita Ranch.

Considering all of the seismic and volcanic uplift required to form the coastal Santa Lucia Mountain Range where Margarita Vineyard is located, it’s no surprise that geological material from all of this ancient volcanic activity is today found on the ranch.

Hot Rocks

Ancient Peaks co-owner and viticulturist Doug Filipponi notes that our volcanic soils come from the rubble of parent material that rolled off the mountain slopes over the millennia.

This parent material includes rocky basalt with distinctive ruddy hues and a high iron content that brings lower yields with excellent flavor concentration.

“Volcanic soils are difficult to grow grapes in, which is why you don’t see a lot of vineyards in the mountainous areas between here and the coast,” he says. “In our case, it results in smaller berries, which for Zinfandel is a good thing. It keeps vigor down, with a higher skin-to-juice ratio that makes for a more concentrated Zinfandel.”

Taste It: 2018 Zinfandel

Our estate-grown 2018 Zinfandel comes from five separate blocks, including the volcanic soils at Block 32. It offers deep, savory aromas of black cherry and plum with notes of vanilla, tobacco and dusty spice. Bright, brambly flavors of red raspberry and boysenberry unfold across a juicy texture with hints of cedar wood and black tea. Fresh acidity adds lift and structure to a sleek, peppery finish.