Q+A with a Dirt Doctor

We sit down with a soil expert to discuss climate change, the future of grape farming and why he chose to grow his own in Napa.

You’ve never heard of Dr. Paul Skinner, but winemakers and grape farmers the world over know him as one of the leading climate and dirt dudes on the planet—after all, wine begins in the ground.

A doctor of soil science and viticulture, Skinner is the founder of Terra Spase, a vineyard-planning firm that’s helped scores of wineries, such as Caymus and Robert Mondavi, find the best ground for grapes. He helped NASA chart weather and wine-soil patterns, and has several farming patents.  He owns Sequum  in St. Helena, where  his vineyard  is  studded with a slew of weather and soil monitors.

You’ve worked all over the world. Why’d you choose St. Helena in Napa for your wines? 
Soil and climate. During peak ripening you’ll have 20 days of fog in the morning and sun every afternoon in the 80–90˚F range, with no humidity—this helps fend off disease and botrytis and the things that people are constantly battling in other parts of the world. There’s rarely rain at harvest, no cold weather. The grapes just keep chugging right along, building flavor and sugar, so winemakers can pretty much pick at their optimum, assuming the vineyards are in good shape. Napa’s special from a climate standpoint. There’s no doubt about it.

What about Napa’s soil?
There are 12 to 15 soil orders in the world, and we have six of those orders here in the Napa AVA. That’s a very good thing and not common.

We all know it’s a key factor, but explain why dirt is so vital? 
You have climate, soil, rootstock and variety. That’s four variables. Mathematically, then, that’s four to the fourth power of potential permutations. That’s a lot. Soils ultimately dictate what kind of rootstocks you can use. So, the right soil provides more control from the start. You can play with those combinations in many different ways. It’s why the wines are really unique. In Napa, we use an incredible amount of sensing technology, use a lot of information for that, and that sets us apart. A lot of places in the world can’t afford that.

So this technology is factored into the prices of Napa wines? 
Because Napa’s wines are on a high level, people are more inclined to maintain that level of quality, and they recognize how important the viticulture is to doing that.

With so many different soils and options, why is Napa so focused on Cabernet Sauvignon?

It used to be, in central Napa, there was Pinot Noir, Chardonnay, Riesling and Gewürztraminer. Then people recognized that certain areas were too warm to grow those varieties. Those varieties gradually went away, and Napa became a red wine-producing environment.

Do older vineyards produce better wines?
Not necessarily. One thing that’s clear is there are usually fewer problems in vineyards that are less than 10 years old.

How worried should we be about water in California?
Water is the foremost challenge right now, even before climate change, because climate is going to change gradually and we may have 15 years to figure out something.

Wineries should start planning for climate change now, yes?
The last three years were pretty ideal. So, it’s hard to rush out and start planting totally different varieties we know nothing about and there’s no market for yet. The models can’t predict where exactly it’s going to change and how much it’s going to change. We’re going to have to wait and see.

Published on December 26, 2014
Topics: Wine News, Wine Trends, Winemakers
About the Author
Virginie Boone
Contributing Editor

Reviews wines from California.

Contributing Editor Virginie Boone has been with Wine Enthusiast since 2010, and reviews the wines of Napa and Sonoma. Boone began her writing career with Lonely Planet travel guides, which eventually led to California-focused wine coverage. She contributes to the Santa Rosa Press Democrat and Sonoma Magazine, and is a regular panelist and speaker on wine topics in California and beyond. Email: vboone@wineenthusiast.net




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