Perfect climate for growing grapes in Eastern Washington
Great wine grapes need sun to aid in the production of sugars (via photosynthesis), color development and heat accumulation for overall flavor and structure ripening. How much sun does Eastern Washington receive?
- While the growing season is slightly shorter from beginning to end than more southerly wine regions, the number of sun hours received in Eastern Washington is equal due to incredibly long days at our northern latitude – receiving up to 17 and a half hours of sun each day.
- There are NO clouds 300 days of year.
- Long days and lack of clouds result in “high light intensity”, a must for great photosynthesis.
- The I longer day length is similar to the great wine regions of Northern Europe, as they share similar latitudes.
Dry Growing Season
Eastern Washington is one of the most northern wine regions in the world. Similar areas elsewhere tend to be on the cusp of cool, rainy weather in the spring and fall, making viticulture difficult – especially at sensitive times like harvest. Eastern Washington is dry enough to be categorized as a Continental Semi-Desert. Why?
- The majestic north south running Olympic and Cascade Mountain ranges in the Western portion of Washington combine to stop the clouds rolling in from the Pacific Ocean, creating a Rain Shadow Effect. Eastern Washington is the most northern latitude wine region to experience this phenomenon in the New World (read: not Europe).
- Only 7 to 12 inches rain fall annually in Eastern Washington.
- Common vineyard fungal disease such as oidium (powdery mildew), peronospera (downy mildew) and grey/black rot require a humid environment. Due to its arid climate, Eastern Washington is remarkably pest and disease free; as a result, very few chemical based fungicides are required, leading to sustainable vineyard practices that leave vibrant, healthy, lively soils and water sources.
Eastern Washington has the good fortune of having incredible water sources to rely on for irrigation in such an arid region. This allows absolute control as to when the vine is given moisture and how much is given, which contributes to grape ripeness, lack of sugar dilution, canopy management and dehydration controls at vital moments during its growth.
Daytime Air and Soil Temperature
- Mountain Rivers: The Columbia Basin benefits from snow melt runoff. The massive Columbia River in Eastern Washington is the most obvious example, combining the Cascades, Rockies and Blue Mountains runoff to the 15th largest river in the United States at 1,214 miles in length.
- Underground aquifers run through levels of basalt lava flow, and can be tapped via wells for water reservoirs. World class, technologically controlled/timed irrigation systems are utilized to influence the growth of many vineyards.
- Drip irrigation is most common, but some overhead spray irrigation also exists.
Consistently warm daytime air and soil temperatures during the growing season are critical to producing the grape varieties that Washington State specializes in, helping with the physiological ripening – including skin color, skin and pulp texture, seed color and texture, tannins and other flavor compounds. Cold (though not freezing – see “Vital Issues” at the end of this section) during the winter months are ideal for vine dormancy, allowing the plant to rest and restore.
Diurnal Shift: Day to Night Temperature Variability
- Average daytime high vineyard air temperatures for June 1 to October 15: 78 degrees Fahrenheit. During the all important August/September months, that average climbs slightly higher to 84 degrees Fahrenheit.
- Average daytime high temperatures for December 1 to March 1: 32 degrees Fahrenheit.
- In addition to allowing proper dormancy, these cold winter temperatures kill many vineyard disease carrying pests such as phylloxera, moths, mites and nematodes. This makes Washington vineyards remarkably pest free. As a result, very few chemical based pesticides are required, leading to sustainable vineyard practices that leave vibrant, healthy, lively soils and water sources.
One of the greatest natural phenomena for growing grapes which end up balanced between ripe sugars (which will equate to alcohol in the wine) and crisp acidity is a difference between day time and night time temperatures – or, diurnal shift. Washington State has some of the most dramatic fluctuations of any wine region in the world.
Different Meso Climates
- There is up to 40º F difference between high day and low night time temps during the decisive Late August through mid October ripening period.
- Malic Acid generally dissipates through respiration from the grape in constant warm temperatures. Cool evenings preserve the acid, which translate through fermentation to wine and adds freshness and balance.
Eastern Washington has 8 separate AVA’s covering over 29,000 acres of vineyard land varying from 100 feet above sea level to 1000 above sea level with all degrees of aspect to the sun. There are cool sites, warm sites, wetter sites, windy sites, hilly sites, flat sites…all providing different ripening cycles and styles of wine.
Good (Bad) Dirt
Vines are somewhat choosy about their soils. A combination of lack of fertility, quick drainage and healthy organic nutrient matter is pretty ideal dirt. It may be “bad” for growing almost anything else, but it is “good” for the vine.
- Various Soil Types: A combination of mostly sandy, rocky based alluvial (meaning carried by water – see below), some windblown over periodic volcanic basalt lift and patches of clay. Types include loess, basalt, clay, silt, loam, sandy loam.
- Ancient Ice Age Floods: Imagine a 300 foot wall of water from a glacial lake just east of Washington gushing at up to 80 miles an hour – 10 times the strength of all the world’s rivers combined – southwest to the Pacific Ocean. More than 50 times over 2,000 years. It happened here 15,000 years ago! That is what a vast portion of Eastern Washington is – a dried up river bottom.
- Low Nitrogen Content: In these types of soils, there is a lack of nitrogen, making vines work harder to send other nutrients to the grapes and spending less energy on the foliage.
- Excellent Drainage: Grape vines don’t do well with wet roots. Sandy/rocky soils drain water further into the earth. Roots dig deep to find it, working harder still.
- Phylloxera Hates Sand: The vine killing aphid, phylloxera (officially known as DactylasphaeraVitifoliae), cannot travel well in sandy soils, leaving Washington remarkably free of this global scourge vineyard pest.
Eastern Washington is one of the very few world class growing regions on earth that DOES NOT have to graft its vines onto rootstock. Phylloxera (dactylasphaera vitifolea) is an aphid that damages roots by feeding on them and leaving them prey to disease and nutrient deficiencies – enough to kill the host vine. It exists in 95% of the world’s quality wine regions. To survive the pest, these places must graft the genus Vitis Vinifera vines (which, while they count for every great wine grape in the world like Chardonnay and Cabernet Sauvignon, are prone to phylloxera) onto another type (or genus) of rootstock such as Vitis Riparia or Vitis Rupestris, which are immune to the pest and able to coexist. While hard to prove, most wine professionals believe that there is at least some purity of flavor lost in having two different vine types forged together. Washington State doesn’t have to do this! As a result, the wines of Washington are 100% the grape variety planted – and that much more profound for it.