The Columbia Valley, home to most of Washington’s vineyards, was formed through the action of the Missoula floods. Some 13 to 15 thousand years ago a series of huge waves of water scoured the region bare, exposing the basaltic and limestone outcroppings that form the bedrock of the region. In the years since this devastating series of floods, which had wave heights of some 400 ft and traveled at a peak of 80 miles an hour, wind blown silty soils have gradually accumulated throughout the region,.
In some spot these wind blown deposits reach tens of feet deep, but they remain essentially free of organic material offering little ability to hold water, though offering the vines an intriguing array of mineral micronutrients for their growth. In general there is a thin layer of topsoil throughout the region as well, but due to the relative youth of the soils, there simply has not been sufficient time for much organic material to be deposited across the region.
This of course is both an advantage, loose soils that allow roots to penetrate deeply into the depths of the soil and access a variety of micronutrients being the great positive. The lack of organic material and generally free draining nature of the soil in a region that is essential a desert being the 900 pound gorilla of a negative in the room. Of course with such little rainfall irrigation is a must in Washington, though a handful of vineyards on the slopes of the Blue Mountains are being dry farmed, though I am not aware of how sustainable those efforts are turning out to be.
Water of course is one of the great issues of our times and nowhere is it felt more acutely than amongst the farming communities of this arid region. In a significant way the future of Washington’s wine industry, and it’s ability to continue to grow hinges on the thorny issue of water rights. At the moment there remains a balance between supply and demand but it is precarious.
Somewhat surprisingly the fine, silty soil that is prevalent in the region prevents the root louse phylloxera from becoming an issue, allowing virtually all the vineyards to be planted on native rootstock. Throughout the world, with few exceptions, this little louse has devastated vineyards as it borrows from root to root sucking the life from vine after vine. In sandy soil though, the carapace of the louse, which in a quirk of nature has overlapping plates that opens towards the front the the animal, traps fine particles of sandy causing the louse to dehydrate and die.
This is important for two reasons. The first is obvious. You can plant vines on their own roots and they don’t die. To many in the wine business there is something special about own rooted vines. The vines and the root remain in harmony, and the wines produced from these vines seem to be more harmonious, and perhaps with a bit less alcohol than vines on American rootstock. Another advantage that own rooted vines have is that if the portion of the vine above ground dies in its youth, due to drought or a hard freeze, the vine that the root produces will be another identical vine. With vines grafted onto American root stock the new growth would be the American variety and not the Vitis Vinifera that was grafted onto the vine.
Whether or not own rooted vines mean anything to the wine buying public at large is certainly open to debate, though in wine geek circles there is no argument that there is something different expressed in the wines produced from fruit grown on these wines. That balance that controls vigor seems to produce wine that have a bit more elegance and finesse, but there might even be something else going on. Something that might explain the ability of so many Washington state wines to retain their savory character even when it is paired with rich, ripe fruit flavors. Again and again I noticed herbaceous notes in Cabernet, and peppery, meaty notes in Syrah that added attractive detail and complexity on the palate. This is mostly like due to the climate here as well, those cool autumn night helping to temper the grapes proclivity to over-ripeness, but I do also believe that the rootstock plays some role in the vines ability to retain varietal character in a way that is becoming increasingly rare in the great growing regions of the world.