Tuesday, October 13, 2009

Why McLaren Vale for vineyards?

The technical reasons behind the hype.

This week I have been doing some volunteer work developing some grape growing information for the McLaren Vale Visitors Centre. This Visitors Centre is staffed by volunteers who represent the region and help face the hundreds of tourists who visit McLaren Vale each day. We all recognise the value of these volunteers and the work they do on the regions behalf. It is important they are armed with information to help guide the visitors to our region.

View from Stump Hill Road looking south east over the town of McLaren Vale.
One of the interesting questions they are often asked by tourist is ‘Why is McLaren Vale good for grape growing?’

McLaren Vale has come a long way in the last ten years. From relative obscurity the region has risen to be recognised as a producer of some of the world’s best red wine.

McLaren Vale; Tree n Vine.
Why is McLaren Vale one of the new world’s best wine regions? You often hear quotes about how the quality of our wines is helped by the regions climate. This got me thinking how many people realise just how special the McLaren Vale region is? Unless we all realise how special it is there is a risk, as farming goes through some hard times, that productive and wonderful land will be chopped up for housing.

McLaren Vale wines are distinguished by their ripeness, elegance, structure, power and complexity.

This is because McLaren Vale is an ideal location. The Mediterranean climate of warm, dry days and cool nights during the growing season assists in development of intense flavour and colour in our wines. Good winter rainfall satisfies the water requirement of the vines until late in the season when some top up is made with subterranean water from our well regulated aquifer, or alternatively from recycled water.

During summer our climate is often shielded from extremely hot weather by the Gulf of St Vincent and the Mt Lofty Ranges. If it rained more in summer or if the region was hit by frosts or heat waves our grape growing would be less reliable.

The grape growers of McLaren Vale have a particular way of speaking about their produce. An old-time McLaren Vale grape grower calls their red wine making fruit- ‘my black grapes’. Modern testing techniques have shown they are right! McLaren Vale Shiraz produces some of the highest colour scores in grapes ever recorded. The grapes are not soft red like other regions. When they are ripe they leave a purple stain.

Blewitt Springs, north east of McLaren Vale.

The reason is simple - small berry size. Smaller berries have a higher skin: pulp ratio. Berry skin contains flavournols (Anti-sunburn in grapes, 'flavour' in wine), Anthocynins (colour) and other complex molecules that add to wine complexity. Grape pulp contains sugar and water. Therefore the more skin to pulp the more complex the wine. Think the circumference of a circle to the area. The bigger the circle the greater the internal area.

Berry size in McLaren Vale is controlled by the vigour and nutrient status of the vine at certain specific times in the vines growth. Regulated Deficient Irrigation (RDI) is a technique to keep berry size small but not overly reduce the final yield. RDI involves placing a moderate water stress on the vines for a period after flowering has finished. This can occur naturally, and is the reason that McLaren and Barossa have been historically been areas for fortified port and table wine. The dry weather in McVale helps because low summer rainfall gives us much better control of soil moisture, the same in the Barossa, in the Coonawarra although it gets much more rainfall, the soil is shallow and runs out of water at about the right time.

While McLaren Vale is best known for producing outstanding Shiraz, the region’s ideal climate and diverse vineyard sites- ‘terrior’ lends itself to ideal grape growing conditions for producing a number of varieties which we are only just exploring.

We make world class Grenache and Cabernet Sauvignon and McLaren Vale grape growers are utilising the region’s diverse range of climates and soils has led to experimentation with emerging varieties such as the fresh whites Fiano, Savagnin, Marsanne and the strong red Tempranillo.

It would be a shame not to continue to work on our natural advantages and protect our wonderful farming land for the future.

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