Understand Walla Walla Valley terroir. Take a deeper look into how regional climate, soils, and winemaking traditions affect Walla Walla Valley wine.
Terroir relates to three aspects that affect how wine tastes.
Terroir ("tear-wah") is a French word and a bit fuzzy to translate in the English language. So, we've broken it down into three aspects of a wine region that ultimately influence what's in your glass.
Characterized as a warm, semi-arid, continental climate, Walla Walla Valley produces red wine varieties that love the sun but can handle a cold winter.
Average temperature from April 1–Oct 31 is 63.5° F (17.5°C).
Continental climates tend to have significant variation in temperature (hot summers and cold winters) and prevailing overland winds. Temperatures are not moderated by bodies of water.
Average annual rainfall is 15 inches (381 m) with just 9 inches on the western side of Walla Walla Valley and 22 inches on the eastern side.
Walla Walla Valley's climate is designed for robust red wine varieties.
There is no lack of sunlight and warm temperatures during the growing season in Walla Walla Valley. Thus, it makes a great spot to grow bolder wine varieties like Cabernet Sauvignon, Syrah, or Tempranillo.
However, winters here are frigid. Every 10 years or so a deep freeze sweeps through the valley that kills vines back to the roots. It's so bad that in some areas vintners bury a cane each year as "insurance." This way, when the freeze kills upper vines, they just dig up the one they buried to grow grapes.
Managing sun helps maintain acidity and alcohol levels.
Too much sun and heat during the growing season causes grapes to become shriveled and overly sweet before the seeds fully ripen. This makes for unbalanced wines with bitter tannins, high alcohol, and low acidity.
In order to manage this, some producers practice spacing their vines closer together so that each row shades the next. By creating a great deal of natural shade, only the vines on the southern edge get toasty.
Dry farming is difficult in the Walla Walla Valley.
The western half of Walla Walla Valley receives only 8 inches (203mm) of rain a year. For perspective, that's less than the Gobi Desert! This means most of the vineyards in Walla Walla Valley are irrigated.
As you move eastward in the valley, rainfall increases up to 22 inches (559mm) of rain, which is nearly enough to dry farm! A few winegrowers in the Mill Creek area and other western forked canyons get enough rain to dry farm.
Terrain & Soils
Walla Walla Valley features 2 main soils that both affect wines in different ways. Learn more about how to find Walla Walla Valley wines you like.
Fine, powdery soils produce highly aromatic wines.
Powdery soils tend to produce wines with more intense floral aromas, finer tannins, and slightly paler color in the glass. This is the main soil type you'll come across in Walla Walla Valley.
It's common to find this soil condition in the valley and the nearby rolling hills. These silky-textured soils don't hold water well but they do go incredibly deep. This means vines grow extensive root systems to extract nutrients.
Here's where you'll see these soils:
- Valley Floor Vineyards: These include vineyards in the Southside District which have soils that include both wind-blown (loess) over Missoula Flood silt deposits.
- Foothills Vineyards: These vineyards exist at higher elevations over 1,200 feet (the Missoula floods high water mark). Although they don't have Missoula Flood silt, they have very deep Loess (wind-blown) soils.
Rocky, volcanic soils bring savory and salty notes to wines.
Rocky soils add minerality and aromatic intensity to wines and volcanic soils add a unique salty-savory quality. This is an exciting soil type in Walla Walla Valley because it's so rare!
The volcanic base here is Basalt and because of this, wines often have a very meaty and iron-like flavor. Key grapes to explore from this soil include Syrah, Cabernet Sauvignon, and Grenache.
Here's where to find these soils:
- The Rocks District of Milton-Freewater: A massive ancient river deposited millions of cobblestones up to 600 feet deep! The cobbles sit within the appellation so you can look for wines that are from vineyards here.
- The River Canyons: There are a few vineyards in the river canyons on the Northfork and Southfork Walla Walla Valley rivers heading into the eastern Blue Mountains. Vineyards here are planted on steep slopes with terraces made of broken basalt pieces.
The Missoula Floods filled Eastern Washington with fine wine soils.
Walla Walla Valley can thank its tumultuous geological history for its great-tasting wines. It all started around 17,000 years ago when an ice dam broke on glacial Lake Missoula.
When the dam broke a massive 400 foot wave travelling 60 miles an hour rushed across Washington state towards the ocean!
Here's the thing, the Missoula Floods didn't happen once. They happened continually over a period of around 2,000–5,000 years as the ice slowly receded with the end of the ice age.
The floods carved out the Columbia River valley. And, each time the waters slowed and settled, they deposited millions of tons of silt across Washington state.
This is why much of Eastern Washington under 1,200 feet is covered with exceptionally fine silt-like soils.