Secrets of the soil

We’re 413 metres up, underneath the peaks of the Dentelles de Montmirail with their chipped limestone teeth grimacing out over some of France’s prettiest villages. The sunlight here in the southern Rhône valley is generous, though spring is barely into its stride; the vines have just broken their buds. You’d never find this Gigondas vineyard without a guide: it’s a terraced carpet of stone, hidden away in a scented forest.

The vines’ owner, Eric Michel of Domaine Crôs de la Mûre, whacks fence posts into the ground with a sledgehammer.

A stoutly built couple are busying themselves around and inside a pit in the vineyard, like a pair of moles. “Look at these roots,” says Lydia Bourguignon. “See how tortuous they are? You don’t want roots as straight as drumsticks. At the greatest domains, the roots are always tortuous; it seems to be linked to the complexity of the wine.” There are some small soil samples, blue with the reagent used for analysis; bigger samples bagged up; a blackboard, notebooks, photographs. The wine world’s most celebrated soil consultants are at work.

Claude and Lydia Bourguignon are, in fact, self-professed outsiders. Both were researchers for France’s Institut National de la Recherche Agronomique (INRA), but left to establish their own Laboratoire Analyses Microbiologiques des Sols (Lams) in 1990, frustrated at INRA’s unwillingness to support the biological analysis of soils. Their espousal of organic and, particularly, biodynamic farming practices has left them outside the soil-science mainstream – but much in demand in the higher echelons of the wine world.

Soil samples

Biodynamics is the holistic farming system based on the 1924 agriculture lectures of Austrian “spiritual scientist” Rudolf Steiner, who argued that farmers need to view their farms as self-sustaining units. Among its most notable features are the use of homeopathic solutions against disease threats, and exotic composts, applied according to a calendar based on planetary movements within the solar system. “The problem,” says Claude, “is that pure science is not good at embracing the complexity of living things. In wine, the rational dimension doesn’t explain everything.”

“You need to believe in biodynamics,” adds Lydia, “to do it properly. By contrast, anyone can be organic; that’s very rational. Our real challenge is working with those who are practicing conventional viticulture, and leading them towards organics. The day we do that, we have won something for the planet.”

In the early days of Lams, their work took them all over the world, working on a variety of challenges with subsistence farmers. As the years have passed, though, wine has claimed more and more of their time – about 80 per cent today.

A vineyard next to Gigondas

Eric Michel is a small grower already producing dazzlingly good Rhône wines from the Massif d’Uchaux, Côtes du Rhône, Gigondas and a few morsels of Châteauneuf-du-Pape. He calls the Bourguignons up from time to time for a specific purpose. On this occasion, it was to look at his organic Gigondas vineyards to try to work out how he could get a little more vigour into the impeccably tended plants, and slightly lift their uneconomically low yields. The Bourguignons suspected organic matter in the upper soil horizon was the issue.

The next day, the Bourguignons moved on to Chêne Bleu, a much larger estate nearby owned by Xavier Rolet, chief executive of the London Stock Exchange, and his wife Nicole. The Bourguignons visit Chêne Bleu a number of times each year, and “accompany” the Rolets as they slowly restore what had been a very dilapidated set of vineyards. I watched them diagnose armillaria root rot in some dying vines, which they did chiefly by sniffing the affected roots in question. “Don’t replant with vines,” said Claude. “Use the plantation rights elsewhere. You could plant olives here – but plant hard wheat first; the fungus doesn’t like cereals.”

Then we moved on to a small, almost hidden valley where the Rolets wanted to plant more vines – but which varieties, and where? Out comes a battered compass. “Full south: Mourvèdre will work well here. You could try Syrah on that northern slope over there; it will give you wines of elegance and finesse.” We drove back to the Rolets’ house. “This parcel will just be for rosé,” said Claude, of a vineyard sloping down towards the kitchen garden. “You’ll never produce good wine here. The soil’s too deep, there’s too much vigour, every bunch will weigh three kilos – it will just give you juice.”

A soil colour chart

The Bourguignons’ client list includes Harlan Estate and Bonny Doon in California, Pingus and Vega Sicilia in Spain, Troplong Mondot and Canon-la-Gaffelière in Bordeaux – and Lafon, Leflaive and the Domaine de la Romanée-Conti (DRC) in Burgundy. They’ve dug no fewer than four soil pits to analyse the soils in Montrachet, the world’s greatest white-wine vineyard, and a single pit in the clay-limestone of Romanée-Conti, perhaps the most prized 1.85ha of agricultural land in the world. Lydia remembers the wry consternation of Aubert de Villaine, who runs DRC. “Do you have to take quite so much soil for your analyses?” They did, however, discover that Romanée-Conti’s clays have a different internal structure to those of Richebourg next door.

A number of concerns preoccupy the Bourguignons: the present drought in France and Spain; the stifling effects of lobbying on scientific research; and industrial agriculture. The evidence of climate change confronts them everywhere. “We now have cicadas in Burgundy. If the climate keeps getting warmer, Pinot in Burgundy is going to have problems: it’s not a variety which likes to be harvested in August or early September.

Of course, in Champagne they are delighted, and in England and Russia too. But for growers in Spain, it might be catastrophic. The plant can adapt, but that will take time. Anthropogenic [human-produced] climate change is too rapid.”

“Things are better than they used to be,” concludes Lydia. “People use chemicals less. There’s no more bad wine. But we are in the middle of homogenising everything, and that’s not what wine is about.” Claude has always shied away from defining himself as an agronomist. “I want to understand the fields and vineyards,” he explains, “not impose my law on them. We are dealing with something incredibly complex. There are a billion microbes in each gram of soil – most of the planet’s living biomass is found there.” Viticulture is interesting in part, he says, because “it’s the sort of agriculture closest to the consumer.” More importantly, though, “it’s where work on the soil can have the maximum effect. And when you work with a soil, you become its co-creator. You help make the future of our planet.”

Claude Bourguignon is speaking at the RAW natural wine fair in London on “Understanding the importance of a healthy soil for the production of wines of terroir”, May 21, 1.30pm (trade day; public entry £20);

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