Wednesday 4 May 2011

Vine age in marginal climates and it’s relation to hydric stress, carbohydrate retention and overall quality:

Last autumn I found myself discussing the benefits of vine age in marginal climates with the esteemed Bill Pannell, founder of Moss Wood and Picardy. It was his contention that vine age made much more of a difference in more marginal climates.
His rationale for this was that in very marginal climates the grapes are left on the vine as long as is possible, this means that we are forcing the vine to carry on working all the way until the very end of the potential growing season. Where as in warmer climates the grapes are harvested earlier, leaving the vine to spend the rest of the growing season replenishing its stores of carbohydrates.
Older vines, with a greater stem surface area (the phloem only runs around the edge of the wood, so volume is less important) and crucially greater root volume are much better placed to ride out any difficulties that might arise early on in the next growing season.
I was reminded of this whilst reading John Atkinson MW’s marvelous study of the terroir of the Cote de Nuits and its effect on wine quality.
He references Franck Wittendal’s principal component analysis that highlighted the soil structure as being the only factor of difference between GC and 1ere etc vineyards that was statistically different.
He goes on to highlight that this provides a buffer for water retention, with the limestone sub soils providing large amounts of calcium carbonate (opens up the soil) and the stony flocculated clay soils allowing for both good drainage and good water retention.
This along with the facility for high root density that is provided by the soil structure and low water density (without reaching stressful levels) means that the vines in the GC vineyards are predisposed to having larger carbohydrate stores, which in  turn allows for better floraison (flower set), which commonly occurs during periods of inclement weather in Burgundy.
Mr Atkinson then goes on to point out that a lot of the GC vineyards have slight easterly exposures that succeed in shielding the vines from excess heat or sun during the final period of the grapes maturation. Essential for the retention of the very delicate floral aromatics that characterizes the best Burgundian wines.
Firstly I can’t recommend John Atkinson MW’s article enough, it was published in the Journal of Wine research,  though was offered to Purple Pages readers free for a while. Secondly it was great to see the Esteemed Bill Pannell’s idea get some extra weight added to it, as he’s one of the most interesting and outspoken wine makers that I’ve had the pleasure of speaking with.

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