The Olifants river wine area was luckier than others in that we did not experience the devastating winds that hit the Boland area late October to early November 2009. This was during the flowering season and caused a lot of damage.
We had another cold and wet winter in 2009 and went into 2010 with a full Clanwilliam dam, enough water in the subsoil and sufficient cold units to effect dormancy and ensure an even bud break come spring. The cover crops established well and the nitrogen- binding leguminous Vetch grew especially well.
One always keeps a beady eye on the weather in January as this is the critical month for Chardonnay and Pinotage and some Sauvignon Blancs. Invariably the first of the vintage’s heat wave puts in an appearance. This can dislocate the up to now hand-in-hand development of sugar and tannins, and skew the situation to high sugars and green tannins.
It forces decisions on when to harvest Sauvignon blanc. Does one preserve the green SB character but run the risk of high acid, low alcohol, or go for riper more complex fruit but run the risk of the heat stripping out the acid and any SB character?
Thankfully the heat stayed away until late February. This led to some of the best Pinotage for some time and the earlier commercial Sauvignon Blanc vineyards in the traditionally warmer areas were of much better quality.
Just as we were being lulled into a sense of complacency we were hit with rain, unusual in both its appearance and intensity. Around the cellar in Trawal we had 70mm and up to 10mm in the semi-arid town of Vanrhynsdorp. No sooner had the rain stopped than we were hit by a heat wave that lasted for two weeks. This was good and bad. It was good for or late ripening red cultivars of Merlot and Cab but made the making of Sauvignon Blanc the most difficult yet.
The heavy rain and humid conditions that followed led to widespread botrytis in the vineyards. This forced us to open up canopies to allow air flow whilst still trying to protect the grapes from sun and heat. As most of the Sauvignon vineyards are near the cold Atlantic coast, the heat effect was less severe.
The extended heat wave arrested what would have been run-away botrytis, and for the first time in the almost 10 years that I have been here, most white vineyards had extensive Noble rot developing, as opposed to the usual sour or grey rot.
This was an opportunity too good to lose and we hand picked the best noble rot bunches from the affected vineyards and look forward to an exceptional Noble late harvest wine.
Having taken the most severely affected bunches out by hand, the vineyard could now be picked for normal wine by machine in the cool of night. Despite the hand picking, the grapes for dry wine still had a significant noble rot component. This brings the risk of oxidative enzymes and pinking. Sulphur dioxide is normally used to deal with this threat but being organic we were limited to the quantity we could use at this stage so we used white tannins as well. To see which wines were at risk from the Laccase enzyme we tried a new kit that showed that, most of the time, this strategy worked to remove the enzyme.
The Sauvignon Blancs have turned out very well with the botrytis adding complexity and depth to the wine.
Extended heat waves like this put the cellar under a lot of pressure but with lots of late nights and ingenious plans we were able to escape any serious problems.
The rain and heat did result in higher transpiration rates in the vineyard which means the grapes picked up more potassium. More acid was needed to achieve the desired acid and pH correction as a lot of added acid was immediately precipitated by the potassium.
The heat wave also underscores the importance of machine harvesters for big vineyards in hot areas. They allow grapes to be picked quickly in the dead of night when it is coolest and allow one to escape the potential damage that hot weather can bring.
The red grapes come from so many vineyards and areas that it is difficult to generalise per cultivar. This is good as it gives us many components to make all the styles we need.
The heat does widen the difference between medium and high potential vineyards and this is especially noticeable by the colour and analysis of the fermenting wine. With judicious cellar work and blending, the vagaries of the vintage should not be noticeable in the finished product
Dudley Wilson June 2010
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