Ode to the Hills: Why Hillsides Make Better Wine
Szabo’s Free RunMarch 23, 2015
Text and photographs by John Szabo MS
“This is where I would plant”, Kevin Pogue tells me as we wind our way up the valley on the north fork of the Walla Walla River near the Washington-Oregon border. I look on either side of the road at the surrounding Blue Mountains, more rounded hills in this part really, covered with pale green wild grasses framed by the occasional outcrop of black basalt bedrock breaking the surface on the thin hillsides and peaking out on the ridge tops in surprising geometric precision. Stands of Ponderosa pines and Douglas firs dot the higher hills in the distance.
Aside from a few isolated patches of young vines that have yet to yield their first crop, vineyards are notably absent. I say notably, because that’s what Pogue is strangely referring to. This is where he would plant grapevines, if he were ever to establish a vineyard. Pogue is a professor of geology at Whitman College in Walla Walla and a respected vineyard consultant – he’s dug pits and analyzed soil structure and chemistry throughout the region, and advised many of the top producers on what, and where, to plant. So it’s telling that he’s pointing to virgin hillsides as the promised land for fine wine – land with no history, no track record to prove its suitability. There are plenty of other areas in Walla Walla, and Washington State for that matter, which have established reputations for yielding good grapes. That’s where you’d think the smart money would go. But Pogue has more than a hunch that these hills are destined for greatness. He knows.
Why Pogue can say this with confidence is not exactly a mystery. Hillsides have been considered prime terroir for fine wine production since long before Roman times. The steeply carved river valleys of the Northern Rhône, Douro and Mosel, the hills that rise up to the Chianti and Soave Classico districts, the flanks of the Vosges Mountains in Alsace, the vertiginous terraces of the Valtellina and the Wachau, the precipitous schists of Priorat, or the volcanic nubs of Mt. Badacsony, Somló and Tokaj that mark the northern edge of the great Plain in Hungary, to name but a very few old world examples, have been celebrated for centuries for the magical properties they impart to wine.
So what is it that makes hillsides so well suited to fine wine? In a word, it’s drainage. I’m referring mostly to water drainage, but air drainage is also important, especially in frost prone areas. Cold air drains off hills and pools, like water, in the lowest spots it finds. In cold climates, this is where you’ll get the most vine damage, which is inconvenient to say the least, even if it doesn’t affect quality directly. Just ask winegrowers in the low-lying parts of Chablis, or Prince Edward County or Washington State or the Okanagan Valley.
It’s About the Drainage
But water drainage on the other hand, does affect quality directly. Indeed, water availability is the single most important quality parameter for grape growing according to every one of the dozen or more soil scientists and geologists I’ve interviewed in the last year.
Here’s the simplified version.
Drainage, or more technically “water holding capacity”, is so important because a vine’s access to nutrients is largely a function of water availability in the soil. Macro and microelements must be dissolved in water first before roots can absorb them.
It’s a fine balance: no water in the soil and the plant dies. But excessively water-retentive soils are equally bad news. When vine roots are immersed in water, they suffocate, literally. Excess water excludes oxygen, which is critical for the nitrogen cycle and other processes that feed the plant.
The ideal – at least from the quality winegrower’s perspective – is closer to the drier end of the continuum. Well-drained soils make nutrients less available – i.e. they are less fertile – and thus produce vines with less vegetative growth, and fewer and smaller but more concentrated grapes (less juice-to-skin ratio) due to the moderate water/nutrient stress. For a winegrower aiming for high quality, this is perfect. Overly wet soils, on the other hand, promote “luxury consumption” of nutrients, which in turn leads to high vigour, high yields and less ripe, more vegetal-flavoured, watery grapes.
Dry soils are also inherently less fertile – they have fewer nutrients to offer the plant in the first place – because they support less natural vegetation. Fewer weeds, grasses or even desired cover crops can grow between vine rows in arid soils. That means less accumulation of organic material derived from decaying plant matter over time. Thus dry soils remain naturally poor in the vigour-promoting nutrients like nitrogen, phosphorous and potassium of which organic matter is composed. Excessive vine vigor, the nightmare of the quality grower, is rarely a problem in well-drained soils. But wet soils, short of an all out chemical war against weeds, are perpetually re-fertilized by organic matter and thus doubly vigorous.
“Physical characteristics are the dominant factor of soil potential”, confirms James A. Kennedy, Ph.D., Professor and Chair of the Department of Viticulture and Enology at Fresno State in California. He’s referring to such things as particle size and the percentage of organic matter and clay (and what type of clay) a soil contains, all of which contribute to its water holding capacity.
I press another California-based soil and viticultural specialist, Daniel Roberts (AKA “Dr. Dirt”) at length for some kind of relation between soil chemistry and wine quality, but he finally shakes his head and raises his hand to stop me. “That soils are well drained is the most critical factor” he declares, closing the door on any fantastic theories I might have had about magic dirt. “Soil chemistry can be adjusted. Soil structure is much harder to adjust. But that’s what matters.” He’s quite right. Soils can, and are regularly amended through applications, man-made or organic. That’s not to say soil chemistry doesn’t matter to wine – it clearly does. It’s just not as important as drainage.
In a similar vein, when I ask Chilean “terroirist” and international vineyard consultant Pedro Parra to describe his “ideal” terroir, the most important factor he cites is: “a very stony soil, with plenty of fractured rocks”. The reason is simple: pebbles and rocks tend to break up the soil, providing avenues for water percolation and root penetration. In other words, he’s after well-drained soils.
No Modifications Required
So why hillsides? Because they come ready-made with low water holding capacity and scarce nutrition. Of course, there are many examples of flat vineyards with low fertility and excellent drainage, mostly on ancient riverbeds full of the drainage-promoting stones that Parra looks for. Consider the gravel terraces of Bordeaux’s Left Bank, the Gimblett Gravels of Hawke’s Bay, the oft-photographed pudding stones of Châteauneuf-du-Pape, or even the new Rocks District of Millton-Freewater AVA in Oregon, sighted entirely on basalt cobbles carried down from the Blue Mountains by the Walla Walla River, for prominent examples. But the fact that these areas also produce excellent wines only strengthens the evidence that drainage is key.
But hillsides are favoured for quality winegrowing because they are invariably less fertile and better drained than low-lying flat ground. They can’t help but drain – they have the natural advantage of gravity on their side. Have you ever seen a waterlogged hillside?
Erosion is also inevitable on hillsides, resulting in shallower soils, that is, less physical soil to hold water or nutrients. And all that soil washed down from slopes accumulates and makes valley floor soils deep and rich in organic matter, and even more fertile and water retentive. Add to that the fact that valley floors also effectively receive double rain – the water that falls from the sky and the water that drains off of surrounding hills, and the challenge of growing quality grapes is further compounded.
On hillsides there’s far less distance for roots to travel to reach the hard, non-water-retentive bedrock. The minimal moisture available is nonetheless sufficient to allow the vine to absorb critical trace elements that have weathered from the bedrock: enough but not too much. If you believe that geology does influence wine flavor, hillsides would be the place to look for evidence.
There are other advantages of hillsides, notably an improved angle for sunlight reception, favoring photosynthesis, and greater air movement, which keeps vines dry and healthy. Higher elevations can be exploited for their cooler temperatures to slow ripening down – critical in hot climates – or to locate vineyards above fog lines or inversion layers (when warm air sits on a dense mass of cold air, and the temperature actually increases as you go higher) to promote ripening. The sugar-acid balance of ripe grapes is almost always better (more natural acid at the same degree of ripeness) on a dry hillside than on a moist flatland vineyard in any given situation.
The downside is higher cost of production. Vineyards planted on the flats are more productive (you can grow more tons per acre) and easier to farm (because they’re flat and tractor-friendly). But on hillsides the yields are naturally low and farming is more labor intensive. In the case of the steepest hills, all work must be done by hand, which increases costs dramatically. The maintenance of terraces and retaining walls to keep soils on the hills are yet other expenses not shared by flatland farmers. In recognition of this, European winegrowers on hills with a greater than 30% gradient have recently sought EU subsidies to help maintain their vineyards, without which many will disappear. That would be a great loss of vinous patrimony.
Of course there are dozens, if not hundreds of other factors than play a role in wine quality. And proper site preparation before planting, such as installing under row drainage tiles, and smart grape growing like regular plowing and applying compost to improve (read: loosen) soil structure can mitigate the negative effects of low-lying, water-greedy soils. But all things being equal, given the choice between the flats and the hills, I’ll always opt for the hillside wine. The vineyards that Kevin Pogue envisions for the Blue Mountains may cost more to farm than anywhere else in Walla Walla, but the results, I wager, will be well worth it.
Buyer’s Guide for the Love of Hills: Great Wines from Steep Hillsides
Set your wine search to any of the regions mentioned in this report to find the wines currently available in your province.
Studert Prüm 2012 Wehlener Sonnenuhr Riesling Spätlese, Mosel, Germany
Dalva 20 Year Old Tawny Port, Douro, Portugal
Taylor Fladgate 20 Year Old Tawny Port, Douro, Portugal
Quinta Da Romaneira 2010 Touriga Nacional, Douro, Portugal
Laurel Glen 2010 Cabernet Sauvignon, Sonoma Mountain, California
Domäne Wachau Dürnstein 2013 Grüner Veltliner Federspiel, Wachau, Austria
Domäne Wachau Achleiten Smaragd 2011 Riesling, Wachau, Austria
Aurelio Settimo 2010 Barolo, Piedmont, Italy
Domaine Des Baumard Clos De Saint Yves 2010 Savennières, Loire, France
Stoller 2012 Pinot Noir, Dundee Hills, Oregon
Hirsch Heiligenstein 2013 Grüner Veltliner, Niederösterreich, Austria
La Moussière 2012 Sancerre, Loire, France
J. L. Chave Selection 2011 Offerus St Joseph, Rhône, France
Prà Otto 2013 Soave Classico, Veneto, Itlay
Carpineto 2012 Chianti Classico, Tuscany, Itlay
Kerpen Wehlener Sonnenuhr 2011 Riesling Spätlese Trocken, Mosel, Germany
St. Urbans Hof Ockfener Bockstein 2011 Riesling Kabinett, Mosel, Germany
That’s all for this Free Run. See you over the next bottle.
John Szabo, MS
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