How does the grape get from the vineyard to the bottle on the shelf? How does soil affect wine quality? What exactly does oak do?
Winemaking – the vine
There are over a thousand different varieties of ‘Vitis vinifera’ (the vine used for wine production) all over the world. The grapes range from the modern types,generated by crossing pre-existing varieties, to the more traditional ones suchas Pinot Noir and Riesling
It is this vine which has been used to make wine down the millennia in the Middle East and Europe, and which nowadays is planted in the New World as well. There are over a thousand different varieties of Vitis vinifera. Each of these varieties produces wines with an individual flavour – many of these such as Chardonnay and Cabernet Sauvignon, have become household names.
Most of the familiar ones, like Pinot Noir and Riesling, have been with us for several hundred years. However, many ‘new’ grape varieties, such as Muller-Thurgau and Pinotage, have been generated in modern times by crossing pre-existing varieties.
Vitis vinifera’s greatest weakness is its susceptibility to an aphid called Phylloxera vastatrix. This vine louse was introduced from Californian vines and spread rapidly throughout most of the world’s vineyards during the second half of the nineteenth century. Phylloxera destroys the root system of the Vitis vinifera, ultimately killing it. There were no effective treatments.
Fortunately, it was noticed that some of the vine species originating in North America, such as Vitis rupestris and Vitis riparia, could cope with Phylloxera. These vines did not produce attractive wines, but by grafting a cutting of Vitis vinifera onto an American vine rootstock, growers were able to replant their devastated vineyards.
Most of the world’s vineyards are planted with grafted vines like this today, everything above ground being Vitis vinifera, and everything below ground being American vine. The main exceptions are vineyard areas like Chile and South Australia, that have to date avoided Phylloxera infestation. In these cases Vitis vinifera vines can still be planted on their own roots.
It takes a newly planted vine three of four years to produce its first crop of grapes. Once in cropping mode, young, vigorous vines yield quite heavily. The quality of the fruit at this stage is often a little simple. As the vine gets older, over thirty years or so, its vigour declines and yield drops. However, what fruit it does produce becomes increasingly concentrated and intensely flavoured. It should come as no surprise that many of the world’s most interesting wines are made from the fruit of old vines.