The Science and Soul of Southwind
Cadaretta’s Soil Composition at Southwind Vineyard
The Southwind Vineyard is just west of Milton-Freewater in Oregon; and is located in the Walla Walla Valley American Viticultural Area (AVA). This estate has unusual and extraordinary characteristics in its soils, and so begins the definition of its distinctive terroir.
Dr. Kevin Pogue, of Vinterra Consulting, is a licensed geologist and professor of geology at Whitman College in Walla Walla, Washington. He holds a doctorate in geology from Oregon State University, and has over 20 years of research experience and teaching at the university level. It was he who Rick Middleton, whose family company owns both Southwind Vineyard and Walla Walla’s Cadaretta Winery, hired to define his vineyard’s soil types. This was done in order to begin to identify Southwind’s terroir, and the flavors that might be irreplaceably ascribed to its wines.
What Kevin Pogue found for the Middleton family was a wow factor… a paradigm shift in our thinking.
Have you heard the Japanese saying, “The nail that sticks out gets hammered down”? This saying is used to make a point about how difficult it is to be different, and that any deviance is met with resistance. With the vineyards at Cadaretta, this is how it is for us… except, the fact that we have something so dramatically different in all of Washington State is this side of astounding. And, it’s not something that we’d like to level out… It’s become the basis for Cadaretta; a distinct defining point of differentiation and not the one nail needs to be leveled to match the rest. It’s the one spot found in Washington State that singularly has the opportunity to define new flavors from ancient soil, with no parallel in the neighborhood. It is truly our unique story and an experiment worth close attention.
What we have at Cadaretta Vineyards are fractured basalt soils, which are unique, as compared to the other 99.9 percent of soil types planted in Washington State. An important feature of this story is that nearly everything in Washington State is planted in flood-derived soils. Whether they’re wind-blown or alluvial, most soils planted here are derived from the non-native granite, which were finely ground by glaciers and redistributed by wind and water.
The Lickskillet Very Stony Loam series, the fractured and decayed basalts that we have at Southwind, are a rare soil type for the region. They don’t happen below 1,250 feet, the maximum height of the Missoula flood. Because of the relatively high elevation, it’s not been historically convenient to develop water to these sites. As a result, this makes them very rare, because it’s so difficult to get water up that high. But when this does happens, viticulturists and winemakers find ancient basalt soils, with their highly oxidized irons and magnesiums. With these elevated calcium carbonate levels, they uncover very different mineral nutrients available to vines, which have a big flavor impact on the resulting wines.
It’s a rarity, and an experiment. It’s very difficult to access soils like this in a desert environment; the site is stony, harsh, sun, and wind exposed.
The Back Story
It’s important to note that terroir is a concept. It’s more than a simple definition, and much more than all that’s tangible. It is a word created by French vignerons, whose families have worked specific vineyards for centuries; where each day their terroir delivers something new to consider. It could simply be a warm breeze on a cool, spring day. Something that simple can affect the outcome of a wine harvest’s uniqueness, if it persists for any length of time.
To gain understanding of terroir for Cadaretta’s, Dr. Kevin Pogue was asked to help, because only the most experienced person would do, in order to get it right. We began by knowing that the soils on Cadaretta’s hillsides are that complex. Initially, we didn’t know exactly how complex that would turn out to be.
In order to begin the process, a hole about 12 feet deep and at least twice as long was dug into the ground. This revealed all of the layers of geologic history:
- Loess ~ Topsoil
- Basalt ~ Midsoil
- Basalt bedrock ~ Bottom soil
Each layer holds certain characteristics and will function in certain ways, affecting the flavors of the wines to be produced; therefore, minerals would become all important as flavor compound considerations.
UPPER: Loess (pronounced as “luss”) is the wind-blown top soil that has a very unique, geologic history. This kind of soil was first recognized in the Rhine River valley, about 1821 A.D. It’s the most common soil type in the Walla Walla AVA, with its local historical roots dating back to the Missoula Floods. Loess was the final layer deposited, when the floods ceased their ravages. We have to return to the end of the Ice Age, which occurred between 15,000 and 13,000 years ago, to get the complete geologic snapshot. This is when geologists estimate that the cycle of flooding and reforming of the Missoula Lake happened… several times, over that 2,000 year period. The floods would periodically sweep across eastern Washington; heading southward, down the Columbia River Gorge.
Another feature of Loess is that it is sediment formed by the accumulation of wind-blown silt, whose mineral origin is quartz and feldspar. It also contains about twenty percent or less of clay materials, and the balance is equal parts of sand and silt. This is all loosely cemented by calcium carbonate. It is usually uniform and highly porous, crossed by vertical passageways, which permit the sediment to fracture and form vertical bluffs.
MIDDLE: Basalt is the midsoil section, and is from the Lickskillet series of soils. Basalt is usually grey to black in color, and rapidly weathers to brown or rust-red, due to oxidation of its iron-rich minerals, into rust color.
This soil type is made up of shallow, well-drained soils, which were formed by stony soil and debris that accumulated at the base of a slope. It is the result of sheet erosion consisting of loess, rock fragments, and residue weathered soil from basalt and rhyolite, all coming together. Lickskillet soils are on uplands, and have slopes ranging from zero to 120 percent. Annual precipitation is usually about 12 inches, and the mean annual temperature is about 48 degrees Fahrenheit.
Its minerality is attributed to an aphanitic igneous rock, which forms when liquid hot, volcanic rock cools and become hard. It also has less than 20 percent quartz; by comparison, granite is more than 20 percent quartz by volume. And, it contains less than 10 percent of feldspathoid; at least 65 percent of the feldspar is in the form of plagioclase.
BOTTOM: Basalt bedrock is the lowest layer of soil in the Southwind Vineyard. Extrusive igneous rocks, or volcanic rocks, form when magma makes its way to Earth’s surface. The molten rock erupts, or flows above the surface, as lava. It then cools down forming a hard rock. It’s dark-colored and fine-grained, and is composed largely of plagioclase feldspar and pyroxene. Basalt is also considered to be one of the main components of oceanic crust.
If the lava cools in less than a day or two, there is no time for elements to form minerals.
FLAVORS OF THE SOILS: All of the above are combining to define the Southwind vineyard in exclusive ways.
Cadaretta’s Southwind Vineyard’s Unique Soil Experiment
With little exception, much of Cadaretta’s Southwind Vineyard has been planted on these Loess soils. These wines will be very characteristic of other Walla Walla Valley wines.
There is, however, an important exception… There’s a location that is high on Southwind Vineyard’s hillside. It’s well above the Missoula Flood elevations, and is consequently in a class all of its own. Loess is thin and the next layer, just below the surface of the loess layer, is undisturbed and decomposed volcanic basalt. It’s easily fractured and it develops into grainy rock soil, which is known as Lickskillet, a stony loam (loam is sand by 40 percent, silt by 40 percent, and clay by 20 percent).
It is these unique, fractured basalt soils, which are so unique as compared to the rest of the state that are is so out of character, and what Rick Middleton and his vineyard and winemaking teams believe will produce a distinctive wine; one that will become the benchmark wines for the Cadaretta wine brand. Dr. Pogue is truly excited about the possibilities. In independent studies, Pogue has discovered important differences of basalt based soils. They have the following:
- More iron content than loess soil.
- Generally retain more heat.
- Measurable differences in grape cluster temperatures, during the middle part of summer days.
Learning what the differences mean for the location that is high on Southwind Vineyards’ hillside is a wait-and-see experiment, as vines have only been recently planted here. But, as with all vines being planted in different locations, it’s a safe assumption that these vines will perform differently, and deliver more unique fruit characteristics. And, the waiting is exciting for everyone involved in Southwind and Cadaretta, as the vineyard moves from test rows to larger production blocks, and the wines those blocks will produce.