The World of Fine Wine

“The viticultural climates of the future will not be like those of today,” says Professor Hans Rainer Schultz. Well, few would disagree. But Professor Schultz’s specific area of study is Riesling in Germany—he is based at the Geisenheim Research Institute—and in November 2008 he gave a presentation in London detailing his researches and his thoughts.

So far, he says, climate change has been beneficial to Riesling in Germany—and indeed to German viticulture generally. Not only is carbon dioxide beneficial to plants, encouraging growth and ripeness, but the rise in temperature noted so far has brought Germany into a more optimum climate. This can be measured with vines quite easily, because the vine has been cultivated for so long and, what’s more, cultivated by the sort of people prone to writing everything down. The record is held by Pinot Noir in Burgundy: The monks kept such detailed notes that we have a database stretching back to 1370. Temperature has been measured directly since the beginning of the 19th century, and while measurements were begun in a cool period, there has been a period—between the 8th and 12th centuries—when the earth was at least as warm as it is now.
And as he says, if you’re a Riesling vine in Germany, the changes so far have all been positive. But it’s not the rise in temperature that is really the problem; it is variability. Cold air can’t hold water, so you get rain. You then need cover crops to take up the rain; but come a drought, those cover crops will compete with the vines. In the Mosel, for example, viticulture is admirably in balance with the environment. But can it adapt?

In the past in Germany—the recent past, that is—cold winters were the limiting factor. Right up until the late 1980s, disastrous years were frequent, and growers were allowed to add water to reduce the acidity in their wine. That’s all changed. Cold winters are much less of a risk, and in 2003, for the first time, German growers were allowed to add acidity. Yes, 2003 was a spike, the warmest year on record, but in 2006 the period from April to October was warmer than in 2003. And if you compare the years 1970–86 with 1994–2007, you find that minimum ripeness is up from 16.3 Brix to 20.7, and acidity is down from 15.5g/l to 9.2.

So far the rise in temperature is comfortably within Riesling’s range; but if predictions for 2050 come true, Riesling may no longer be comfortable in Germany. Southeast England may be the beneficiary, but that could mean goodbye to wines that combine low alcohol with power and flavor.
Then there is the question of water. Dry vineyard sites and steep slopes need water. There is no infrastructure for irrigation, there are no water rights in place, and there is more water run-off and more release of CO2 from the soil as organic matter decays. Some cover crops can take CO2 back again, it’s true. Terraces are better at retaining water, but Germany has done away with terraces. Irrigation changes the character of wine, too—often for the better, in a drought. Aroma can be improved and bitterness reduced. But at the moment, the infrastructure by and large does not exist.
The plasticity of a variety, says Professor Schultz, is its capacity for adaptation. Chardonnay is like a weed, in that it can grow almost anywhere. But Riesling? We really don’t yet know its maximum plasticity. Sooner or later, we will find out. But at least for the moment, so far, so good.

This article originally appeared in Issue 24, 2009 of The World of Fine Wine magazine, a quarterly magazine devoted to wine and all thing vinous.

It boasts an authoritative cast of writers—including Huon Hooke, Andrew Caillard MW, James Halliday, David Schildknecht, Jancis Robinson MW, and Oz Clarke—contributing some of the most original writing published today, under the editorial baton of Neil Beckett. Find out more at the magazine website: www.finewinemag.com

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