The Trefethen Family Blog

Most days, here at Trefethen Family Vineyards, I’ll go for a run through the estate vineyards that surround the winery. It’s a great way to unwind after the arduous rigors of tasting wine all day (insert winking emoticon). The dirt roads between the vines are soft on my aging knees and you can’t beat the view. It’s good to remind yourself, every once in a while, that you work in a vacation spot. Although I can’t say that I inspect every vine as I go by, I do notice important things like a broken irrigation line or when a vineyard block is in bloom.

Recently, on the second day of an El Niño downpour, I laced up the shoes and hit the vineyards. I had missed a run the day before and, like many runners, the thought of missing two days in a row filled me with a bit of anxiety. As I ran that day, the French word “terroir” came to mind. Terroir—often translated as “a sense of place”—is used to describe the soil, topography, and climate of a grape-growing region. The feeling is that the terroir of a vineyard will impart a quality or a certain personality to the wine that is unique to that vineyard or region. American winemakers will occasionally roll their eyes at the mention of the word (I admit I can’t help but use “air quotation marks” every time I say it). That’s because terroir is often used by Francophiles to argue that, regardless of the quality, Napa Cabernet will never be as good as Bordeaux because Napa doesn’t have Bordeaux’s terroir. That argument aside, the idea that certain regions grow certain varieties of grape more successfully than other regions makes perfect sense.

Trefethen Family Vineyards has 440 vineyard acres and extensive soil surveys over the years have identified over a dozen different soil types surrounding the winery. Although each vineyard block experiences the same climate, drastic differences in the fruit produced can be seen between adjacent vineyard blocks, and these differences, for the most part, have to do with the type and structure of that soil. To my mind, the biggest factor in determining which soil is suitable for a grape variety is the water retention of the soil. For instance, Cabernet sauvignon needs well-drained soils in order to completely ripen its fruit before the vine goes dormant for the winter. When grown in deep and heavy clay soils you get what the old-timers call “wet-feet Cab”—Cabernet that never ripens and makes a wine that tastes like canned green beans. On the other hand, earlier ripening varieties like Chardonnay or Merlot, grown in that same soil will fully ripen and make a beautiful wine. My rainy run that day gave me an unexpected lesson on how all of those soil surveys helped the vineyard team choose which varieties of grapes to plant in each section.
Cabernet Sauvignon
Patting myself on the back as I exited the winery building—it’s pretty hard-core for a Californian to run in the rain—I headed down a muddy vineyard row into the area where most of our Cabernet Sauvignon was planted. There’s a winter creek at the north end of the property that, before we had levees and storm-water control, would jump the bank and carve new routes all the time. This land has lower clay content, and if you dig down a couple feet, you will find the subsoil full of old, gravelly river rock deposited by the creek over the centuries. This rocky subsoil means good drainage and rarely a puddle. The traction got better the closer I got to the creek leading me to conclude that what’s good for Cab is good for running.
Chardonnay
I veered away from the old creek bed and realized that I was in for it. Soil surveys showed a line of subsurface gravel that runs through this block that allows for decent drainage but the topsoil is a clay loam that soaks up water like a sponge. Because of the subsoil, the ground will dry out before summer and the Chardonnay planted here ripens earlier than in other parts of the property. Unfortunately I wasn’t running on the subsoil.  An El Niño winter combined with the clay loam topsoil to make a spectacular mud puddle. This was a special kind of mud—the kind of mud that you could use to mortar a brick wall or to trap a mastodon. I was growing taller with each step as the clay caked into the tread of my shoes—building my own pair of mud stilts. My shoes were as heavy as cinder blocks. Every once in a while I would kick out a foot and send a couple pounds worth of clods sailing into the dormant Chardonnay vines.
Riesling
As I struggled out of this Chardonnay block, the clods started disappearing from my shoes but I encountered a different problem. Glancing ahead to where the majority of the Riesling is planted, I was startled to find a wetland transplanted into the vineyard—complete with egrets and ducks wading through ankle-deep water. This block has an even heavier soil with a water-holding capacity that allows us to dry-farm—we don’t irrigate all summer. Even with dry-farming, the Riesling in this block ripens later than Riesling in other areas—giving the fruit from the different sections distinct characters. Rather than join the water fowl, I detoured onto a gravel road to the southern end of the property.
Merlot and Pinot Noir
I was now at the opposite end of the vineyard from the winter creek and running through Pinot Noir and Merlot vines. I was cautiously optimistic—no big puddles but what should have peaked my curiosity were the ruts where farm equipment had gotten stuck. Everything seemed fine until I decided to kick up the pace and almost kicked myself in the back of the head. To say that the ground was slick would be an understatement. We’ve dug pits in this area and found a hodgepodge of different soils, and I felt it—two steps fine, one step like running across bacon grease. The land had good drainage, but something about the water-saturated silt-loam lacing this topsoil made for groin-pulls.

The grapes from these vineyard blocks ripen with that same variability, so our vineyard team has split up these blocks into two dozen independent irrigation zones to try to even things out a little. Even with this kind of precision farming, these vineyard blocks are usually harvested in several passes due to the soil variability. It is always interesting to see such complexity in what, from an aerial photo, looks like the same land. Food for thought, as I gingerly high-stepped along this section—trying to run without fully committing to each step. I was wondering how I would convey how far I ran in my running log. Technically, this section was a half mile long but it felt like I was running the wrong way on a people-mover. That has to be worth an extra quarter mile, right?

As I pulled back into the winery, and hosed the terroir off my shoes, I thought about how lucky I was to have the opportunity to experience wine from its creation to appreciation. There certainly is much to learn about wine, and each harvest teaches me a new lesson. I also decided that, in the future, I’d rather learn about soil structure from a survey map than a mud-run.

Cheers,
Zeke Neeley
Winemaker