Figure 1 Water deficits in mm: 2009vs2005vslongterm trend. Cote de Nuits
Below (Angleterroir? post) I drew attention to the water requirements of anisohydric grape varierties – pinot noir, syrah, merlot – and the fact that in non-irrigated regions they can be acutely sensitive to droughts, whereas isohydric vines – cabernet sauvignon, grenache - can better regulate and maintain vine water status through control of leaf stomatal aperture. We might extrapolate from this that in Bordeaux, cabernet has a greater overall affinity with the region's rapidly drying sand and shingle soils than does merlot, and (Angleterroir? post) this might account for the synergy between merlot and the smectite clays of Petrus.
In 2005, Burgundy’s summer was very dry, though spring rainfall levels had been plentiful. Through July and August the difference between vine evapotranspiration and precipitation became acute, reaching levels that would ordinarily impair vine metabolic function and nutrient uptake (P at flowering; Mg/K/Ca between flowering and veraison). The vines that were best able to cope with this drought-regime would have been those that had access to a supplementary source of water. The proximity of limestone aquifers, and their capacity to capillary feed moisture into the overlying soils would have been hugely advantageous in the CdN's better Crus, whilst superficially rooted vineyards planted on deeper soils may have much been less tolerant of the anomylous climatic conditions.It will be interesting to follow the fortunes of the vintage, which when it came to market was highly acclaimed. It may well be that for the reasons outlined above, the wines turn out to far less consistent than was originally thought.