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What a Difference a Year Makes

Or, Summer Hot, Some Are Not

By Harry Peterson-Nedry

Vintage differences play an almost mythological role in wine appreciation. We've all witnessed the pretentious James Bond-ish "Tell me what this wine is and what year" game, followed by, "Ohmigod, that's exactly it—how do you do it!?" Makes you gag and not want to be anything close to a wine snob—almost convinced that vintage shouldn't make a difference if it's to be used as a parlor game.

The Willamette River, working its way inexorably through Wine Country with the Dundee Hills and Chehalem Mountains in the background toward a juncture with the Columbia River north of Portland, is both a source of vital water for the agriculturally rich valley and a symbol of a finely balanced environmental stewardship we must embrace in all facets of our lives—all of us, from wineries to agriculture, industry, and individuals. However, vintage differences ARE real, especially in cool-climate regions where wines best reflect true varietal character, nuance, and complexity. In Oregon's Willamette Valley, we see the rich fabric of vintage differences in spades. And, there is no better time to experience vintage diversity than today, with the 2006 vintage capable of being foiled by either 2005 or 2007—three vintages with equivalently good but distinctly different wines.

We are in the midst of releasing 2006 Pinot Noirs, from a vintage I would classify as beautifully warm—almost as warm as the globally searing 2003 vintage—but with redeeming acidity and balance in its buxom frame. Compare this fully ripe vintage to the cool-climate sandwich years of 2005 and 2007, in which the growing seasons were cool, and the impression is of finesse not size, defined by brightness and flavors not structure.

The secret of great, ageable wines is simply balance. In hot years, powerful forces like alcohol, tannin, and color predominate and need to be integrated. In cool years, acid, fruit, and spice are present in an environment of moderate ripeness, with alcohol, tannin, and color being restrained. As long as the wines are balanced by complementary elements, wine quality is high—e.g., adequate acid to balance fleshy fruit or large tannin structure in warm years, or more structure and ripeness to balance high acid in cooler years. (See Molly Hodgin's explanation of how grapes respond differently in hot versus cool years in In The Vineyard.)

Well-balanced wines free us to focus on the nuances and rich diversity of variable vintages. I liken them to a dynamic, prosperous, bustling urban downtown, without poverty and ostentation, roiling with different skin colors, multi-textured dress, spicy aromas of ethnic food vendors, and warm, bubbling sounds of languages mixing.

Pinot Noirs from these three vintages, 2005–2007, are currently or soon-to-be available and prove very instructive, showing how widely disparate vintages can be equivalent in quality and intriguing in their rich differences.

Cassandra is Listened To

Although it may raise rancor in some, I'd like to beat an old and battered drum—that of Climate Change—since it is very germane to both vintage differences and the cool-climate attributes that make Willamette Valley wines magical. At last, as conditions become so obvious that even those with their heads in the sand cannot deny them, there is broad agreement that we must do something about climate change.

If Americans still need convincing that Global Climate Change is a reality, the Oregon Wine Industry may serve both as proof that our environment has indeed changed and as a case study on what steps to take as we address change.

Oregon is now known worldwide as an ideal home for finicky cool-climate grape varieties such as Pinot Noir, Riesling, Chardonnay, and Pinot Gris. These delicate varieties require cool-to-moderate growing seasons to retain finesse and elegance, keeping bright, fresh fruit acids while barely reaching full ripeness in our shortened seasons. The marketplace is now hot for what we uniquely grow here—ironically, as the valleys heat up as well.

Heat Accumulation in Recent Vintages Compared to Average

Degree days are easily computed for growing seasons, showing relative heat available in one vintage versus another or compared to long-term averages.

Being sensitive to the precarious balance we enjoy, winemakers have long monitored weather data for predictive signs of what vintages will be like and what needs to be done to optimize ripening. This data also shows how the wine industry is a "canary in the coal mine" relative to longer-term climate change. And what can be seen is sobering.

Currently climates like ours benefit from gradual climate changes, but as change continues, steps must be taken to both slow and hopefully stop this change, as well as to adapt to the warmer future as it unfolds.

Grapegrowing and Political Climate Change

The climate data I see today differs considerably and progressively from the data I saw three decades ago. More people now embrace the reality that our climate is changing globally than did eight or so years ago when I began raising the topic and relating it to grapegrowing. Regrettably, at first it became politicized nationally and was argued stupidly from the poles of party politics. Now, even those vested in CO2-generating industries like oil, automobiles, and energy have lost the will to fight the technical rigor and social cause celebre that Nobel Peace Prizes bring. About time!

But that's easy for me to say, having a scientific bent and being in an industry with an agricultural nature that makes it innately sensitive to weather variation. There is a mystique wrapped around how one year, or vintage, differs from another, based on heat, rain, early and late seasons, heat spikes, cool nights, and the like. And, in the Willamette Valley, where a large percentage of Oregon’s wine industry resides, we are even more highly attuned to weather. We are a Cool Climate Viticultural Region, like other areas where many of the finest wines of elegance and finesse are grown, e.g., Burgundy, New Zealand, Alsace, Germany, Austria, and even Bordeaux.

The beauty of cool climates rests on their ability to only barely ripen wine grapes, so that acidity is not burned out and finesse and food friendliness are retained. A climate that is too warm with cool-climate grape varieties like Pinot Noir, Riesling, Pinot Gris, and Chardonnay yields clumsy, overly alcoholic and coarse wines. A climate that is too cool fails to ripen the grapes before fall rains or freezes, leaving you with a green-tasting, highly acidic wine.

On the cusp as we are, it is important to monitor climate assiduously. And from this analysis it has been evident for a decade, and especially so now, that our climate is changing, here and across the globe. But let’s stick to here.

At Chehalem, we measure the heat for each growing season so we know how much photosynthetic capability we have during a vintage. We can do complex or very simple calculations to track heating over the year, and the simple ones are just fine. I use national weather stations at local airports like McMinnville or weather stations in our vineyards for data, recording how much above 50°F the high is for each day, with very hot days above 90°F being ranked down, and adding those degree counts together for a cumulative annual total.

Willamette Valley Heat Summation by Vintage

Climate change is real. Over the last 11 vintages, heat accumulations have met or exceeded the average from the 30 years ending in 1990, the probability of that occurring by chance alone, without a change to the underlying system, being 0.1%, or one in a thousand.

"Cumulative degree days" is what this statistic is called, and it clearly shows the distinctions between warm and cool years, which in cool-climate viticulture is often the difference between great years and not so great years.

What have we found? Over the last 12 years, Oregon Pinot Noir has finally lived up to its potential, with 9 years being dry, warm, ripening, and excellent in quality. Only 3 years showed what in past decades were typical "Oregon Vintages," ending with rain at harvest and only good wine quality. Vintages that then were most common.

Another startling observation using this degree-day statistic is to notice that the last 11 years have had heat accumulations equal to or above the 30-year average of 1961–1990. If no change had been experienced in those 11 years, we would expect degree days to bounce around on either side of the average, with approximately half on the higher side and half on the lower side. The probability of 11 vintages in a row at or above average occurring by chance alone is easily calculated at 0.1%, or a one-in-a-thousand chance. Climate change is a reality in the Willamette Valley—demonstrably so—and we don't have to take ice cores at the polar cap or anything tough to prove it.

Despite the specter of climate change, it is not doing damage to the wine industry today in cool-climate areas. Much the contrary, we've seen our best vintages under this new climate regime.

We care nonetheless, because change continues. We care because the freight train isn’t stopping after dropping off our recent stellar vintages. It's picking up steam and speed, and we must find ways to slow the imminent changes.

Dr. Greg Jones, Oregon's global wine-region climate expert, delineates a Pinot Noir climate niche worldwide between 14° and 16°C (57–61°F) daily mean temperature, and notes that a warming of up to 1.9°C (3.5°F) has occurred over the last 40–50 years, with an equivalent warming of 1.7–2.2°C predicted between now and 2050. Changes in extremes for rain, frost, etc. bring even greater uncertainty. This means that what is currently appropriate territory for Pinot Noir will likely not be suitable in the future, except through adaptation.

Adaptation

The grape varieties that call the Willamette Valley home will either change over time, as we investigate Syrah, Tempranillo and other Italian varietals, Grüner Veltliner, adaptable Riesling, or new clones of old varieties; or, they will be asked to live in areas that would be unusual today. We'll consider high elevations well above the current 700-foot rule of thumb maximum, strange aspects such as the north sides of hills (not south sides), and locales not heretofore suited for grapes such as the Coast Range, southwestern Washington, or the Cascade foothills.

Drip irrigation technologies, even in stingy, dry growing areas, will be necessary. Adjustments to crop loads and harvest dates will try to accommodate warmer growing conditions and higher sugar levels. Adaptation in the winery will use technologies to reduce alcohols during and after fermentation and to control processes more precisely.

All businesses and private contributions to environmental problems must be critically evaluated, an effort already underway, notably in the Carbon Neutral Challenge sponsored by Oregon state government, to which the wine industry was the first to sign up late last year. (We’ll report in our next newsletter on insights and planned changes Chehalem has underway as part of this challenge).

Can Do

Despite the size of the challenge we all have in front of us, there is reason for optimism. It is both possible and affordable to attack climate change and improve our environment. As the UN study on climate change concluded in its Fourth Assessment Report:

There is high agreement and much evidence that all stabilisation levels assessed can be achieved by deployment of a portfolio of technologies that are either currently available or expected to be commercialised in coming decades, assuming appropriate and effective incentives are in place.

Plus…

In 2050, global average macro-economic costs for mitigation…corresponds to slowing average annual global GDP growth by less than 0.12 percentage points.*

We can’t afford not to do it.

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*Summary for Policymakers of the Synthesis Report of the IPCC Fourth Assessment Report DRAFT COPY 16 NOVEMBER 2007 23:04 (To read the full draft... )