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 contains some distinctive soils that help to define its exceptional terroir.
According to Dr. Kevin Pogue:
“The soils in the “fractured block” are distinctive. What makes them distinctive is that the surface layer of loess is relatively shallow, allowing the roots of the vines to penetrate into the underlying fractured and weathered basalt bedrock, which has a different mineral chemistry (more Fe, Mg, Ca, less K, Al, Na) than the overlying loess. The block is on a slope that faces south and southwest, into the sun and prevailing wind direction. The thin soils, as well as enhanced exposure to sun and wind, induce vine stress. This is generally associated with grapes that make better wines.”
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 25 years of teaching and research experience 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 characterize and delineate 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 was an area of their property that they had not planned to plant because they thought the soils were too shallow and rocky. Pogue advised them that it might actually be the best place to plant if they wanted to make interesting, terroir-driven wines.
“Southwind Vineyard and Walla Walla’s Cadaretta Winery hired me to characterize their soils, and I told them that they should consider developing and planting the Lickskillet soils on their property I felt that this would add diversity to their terroir portfolio, and was likely to give them grapes for exceptional wines. The adjacent Seven Hills vineyard has a block planted on Lickskillet soils. I knew that this would be something new and interesting for Southwind, adding to the diversity of what they offer with their Cadaretta wines.”
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 for the fact that we have something so dramatically different in our Oregon vineyard. 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 Oregon that singularly has the opportunity to define new flavors from ancient soil for us. It is truly our unique story and an experiment worth close attention.
Cadaretta Vineyards contain fractured basalt soils, which occur on steep hillsides all over the Columbia basin, as compared to the other 99.9 percent of soil types planted in other areas of the states. Whether they’re wind-blown or alluvial, most soils planted in the Basin are derived in part from the non-native granite, which was 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 common on every steep, hillside soil type for the region. They’re not present, however, 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. They’ve not been developed for viticulture, primarily because they are thin, rocky, and occur on steep slopes where cultivation is difficult. A challenge is that it’s so difficult to get water up that high (which is not the primary reason, however). But when this does happens, viticulturists and winemakers find ancient basalt soils, with highly oxidized iron and magnesium, as well as elevated calcium carbonate levels. This results in a distinctive assemblage of 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 this semi-arid environment; the site is stony, harsh, sunny, 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, 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 they 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
- Fractured and decomposed 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 distinctive 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 the impounding and catastrophic draining of Glacial Lake Missoula Lake occurred… dozens of times, over that 2,000 year period. The floods would periodically sweep across eastern Washington; heading southward, down the Columbia River Gorge.
Loess is sediment deposited by the wind. It is composed mostly of silt with some fine sand and is poor in clay. Loess in the Columbia contains the minerals quartz and feldspar, derived in part from granite. 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: Fractured decomposed basalt is the midsoil section, and is from this Lickskillet soil type. Basalt is usually grey to black in color, and rapidly (only in wet climates) weathers to brown or rust-red, due to oxidation of its iron-rich minerals, into rust color.
The midsoil was formed by stony soil and debris that accumulated on, or at the base of slopes. It is composed of loess, basalt, and weathered basalt all coming together. Lickskillet soils are on uplands, and have slopes ranging from zero to 120 degrees. Annual precipitation is usually about 12 inches, and the mean annual temperature is about 48 degrees Fahrenheit.
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.
It is the presence of these unique, fractured basalt soils, which are so unique as compared to the rest of the state (which state?) that 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, calcium, and magnesium content than loess soil.
- Generally retain more heat more quickly (only if basalt fragments cover the surface)
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, anticipating the wines those blocks will produce.