IN THE PACIFIC NORTH WEST, it sits above Oregon and below the Canadian border. Fly into Seattle, and beyond the city boundaries you are faced with a lush, green landscape, well watered by the seemingly incessant rain. But drive inland a couple of hours, heading east over the Cascade mountains, and it’s as if you have entered another country. This is practically desert, without enough rainfall to dry-grow vines. But the warm summers and lack of rainfall make it a good place for wine grapes, for here there is no shortage of water from the mighty Columbia River, which is the fifth largest in the US. This ready supply of irrigation water has made this an important agricultural region, known for its hops, cherries, peas and apples. And now wine grapes.
If you look at the figures, there’s no doubt wine is doing well in Washington State. The first AVA was the Yakima Valley, established as recently as 1983. Then, there were just 40 wineries here. Now there are 850 licensed wineries in the state (although for various reasons – such as some wineries having more than one licence – this is certainly an overestimate of the number of ‘real’ wineries, which is closer to 600).
Currently, the wine scene is growing by just under 9% a year. Vineyard area is now at 57,000 acres (23,000ha), which is double the size of Oregon, but it has the potential to grow to 200,000 acres (81,000ha – almost the size of the whole of South Africa’s vineyards).
Because of the lack of rainfall, soil organic content is low. The soils are predominantly sandy and loamy over basalt with a thin layer of loess on top (loess looks a bit like ultra-fine sand: fine-grained and made up of dust-like grains). Vines are usually grown own-rooted here because phylloxera can’t cope with the sandy-ish soils. And there’s very little disease pressure because of the lack of rain. The main hazard is winter cold, with extreme lows liable to take out vines from time to time.
The state’s reliance on irrigation does have one advantage, though, because careful control of irrigation can help with wine quality. In particular, switching irrigation on and off at the right time can regulate berry size at the cell division stage, and this is research that has been carried out at Washington State University.
A significant geological event helped create the terroir in the Columbia Valley. “What happened here 10,000 years ago made this a great wine region,” says Chris Upchurch, winemaker at Delille Cellars, referring to a series of dramatic water events known as the Missoula Floods. “We imported all our soils from Utah, Idaho and Montana.” These floods occurred several times, around the end of the last ice age. A massive lake, 700m deep, was bounded by glaciers. When these melted and failed, the water was released, creating a huge wave. “In Missoula you can still see on the hills the layers where the lake was,” says Upchurch. “This was discovered by a park ranger in the 1920s.” The fact that this great mass of water couldn’t pass quickly through the Wallula Gap (a narrow break in the basalt folds along the Columbia river in the south of the state) meant it had plenty of time to deposit sediments (slack water deposits) which now form many of the soils in this part of the state.