Have you ever thought about the origin of the wine you’re drinking? Senior science curator Susan Waugh looks into the geology of a French region famous for its sauvignon blanc and pinot noir.
As the notion of terroir develops more strongly in New Zealand, I carried out a bit of light research of my own into this concept in the home of sauvignon, in the region of Berry, in the centre of France, while visiting my French family over Christmas 2016-17.
Recent research into the characteristics of the NZ wine regionalisation (see Imre & Mauk’s very accessible scientific article from 2009) showed that in contrast to wine-growing areas where premium wines are produced overseas, NZ wineries tend to be located on flat land, and were concentrated on alluvial (predominantly greywacke) soils. This is true at least for the sauvignon blanc production, which dominates by area and volume in New Zealand. In other parts of the world, vineyards may have more varied soils and on more sloping ground.
How landscape influences the grapes
I went for a visit to the famous wine-growing region of Sancerre, which produces sauvignon blanc and pinot noir wine varieties.
The first sauvignon is thought to originate in this region and in the Bordelais region (around Bordeaux, further south and west).
The name sauvignon is thought to originate either from the Latin ‘sylva’, meaning forest, or from the French ‘sauvage’ in relation to its taste (various sources discuss worthwhile aspects of its bouquet and palette (eg grapefruit, eucalyptus, vanilla), but also one described as ‘pipi chat’ (I ask myself, who has tasted this, to provide an authoritative taste reference?!).
I did a winery tour chez Henri Bourgeois in Chavignol, a family winery that also produces organic wines in Marlborough under the label Clos Henri.
Their tour guide, Jean-Michel Fenioux, gave us some fascinating insights into the production and the particular aspects of the landscape that contribute to the terroir of their wine.
Far from seeking uniform and easy-to-manage growing substrates, the wine-makers in the Sancerre use the natural differences between varying parcels of land on different slopes in the valley, and the underlying geology to accentuate the variety of tastes produced in their wines.
Bringing French lessons to New Zealand
The Henri Bourgeois winery separates wines from different parcels of land throughout their refinement and production, with the effect that even within the one winery, there were several distinctive tasting wines produced, all under the Henri Bourgeois ‘Sancerre Blanc’ variety (eg La Côte des Monts Damnés, La Bourgeoise, Etienne Henri).
Interestingly in Marlborough, this same wine producer has sought out a parcel of land which contains several soil types, both greywacke and clays, intersected by the Wairau fault-line, to ensure a variability in tastes in the wine they produce.
Slope (steepness of the hills) and aspect (the direction the land faces) are key features, as are the soil types. In the Sancerre area, there are geological formations from the Eocene, Cretaceous, Jurassic and Quaternary eras.
The Loire River, before it gets huge and monolithic (and peppered with chateaux), winds its way through the Berry region, and the erosion has cut through the rock formations, leaving a veritable layer-cake of geological variations exposed across a very small surface area, from hill-top to valley-bottom.
Thanks to Le Goût de la Terre 2004 exhibition at the Museum of Bourges on the influence of geology on wine-growing, and a very knowledgeable French side of the family (thanks Rosemarie…), I was able to do a rapid ‘cram’ of this topic. In Sancerre, more than 300km from the sea in any direction, who would have thought that the main substrate is based on marine sediments, with alternating layers of calcareous sediments and marnes (a soil composed of 35% calcite and 65% clays).
As we walked around the winery at Chavignol, we found ancient fossil marine oysters shells in the soil, and brachiopods which have evolved across the eons, provide reference points of the age of these formations. The main formation is the Kimmeridgian, aged at around 145 million years old, renowned as a soil that produces premium wines. What came first? The refinement of wine-growing on this soil type, or a soil that gave consistently great-tasting wines?
Terroir and savoir-faire: A recipe for success
There is no question in any bit of French wine-related literature you might pick up that the taste of the wine results from an interplay between the terroir (the geology, which affects the drainage, mineral components, root formation, microbial components of the soil; climate; the slope and aspect of the land) and the savoir-faire (‘know-how’), such as the horticultural aspects (cepages = varieties, pruning, soil treatment, disease management) and the work of the artisans who turn the grapes/juice into the good drop.
The myriad wine tastes, evident even in the differences between parcels of grapes grown on different sides of the same valley, is due to this complex interaction, in which the natural history of the land is one vital component.
As noted in the 2009 review of New Zealand terroir, our winegrowers are beginning to explore the properties of land on more sloping areas and diverse soil types, we should expect new wine tastes to result. Perhaps the New Zealand terroir will further flourish and define its own distinctive style.
And then we move on to the question of cheeses…
References and acknowledgements:
Thanks to Rosemarie Filippi, formerly of the Museum of Bourges, for information and analyses on the Berry wine growers and materials on the exhibition Le Goût de la Terre, which she co-curated in 2004.
Thanks to Jean-Michel Fenioux and the staff at Henri Bourgeois for their warm welcome and informative tour.
Filippi, R. (2007). Catalogue des brachiopodes mesozoiques conservés au Muséum d’Histoire Naturelle de Bourges. Bulletin des muséums de la region Centre. No. 20. novembre 2007. Muséum d’Histoire Naturelle, 18000, Bourges. ISSN 0395-8957.