You've probably noticed that in the past few years the marketing people have decided that you want to buy your wine according to the variety of grape from which it was made. Once upon a time a wine label told you in big letters where the wine was made, now it tells you in big letters what grape it's made of. Cabernet Sauvignon and Chardonnay labels are ubiquitous and other varieties are gaining their own following. But you may like to know how all this started.

If we go back to basics all vines are descended from the wild 'vitis vinifera', which translates as the 'wine-bringing vine'. A long time ago the first differentiation was made between table grapes, which were good to eat, and wine-making grapes whose characteristics best suited them for that job. Man is nothing if not inventive, and vineyard man (homo vineus) soon learnt that selective breeding allowed him to select and propagate the characteristics he most wanted.

There are several ways to do this, all of which depend upon the natural mutations that all plants produce. Firstly you can grow from seeds, and every now and then a vine will grow with some new and possibly useful mutation. You can save the seeds from those grapes and after a generation or two you'll get a new and stable variety. As the science of selective breeding became better understood after Mendel, vines were cross-bred to develop useful characteristics and grafting a shoot from one vine to another's root stock became common practice.

By these methods vines were developed to fulfil different climactic demands, for example the Muller-Thurgau was bred to mature even in the relative cool of northern Germany and a lot of research is ongoing in California in search of grapes for hot climates. Today there are upwards of 300 variants of the Pinot Noir, each with slightly differing characteristics such as earlier or later maturation, giving a grower the opportunity to pick a grape perfectly adapted for his particular terroir.

Wine of the Week

Shalistin 2001, Langhorne Creek.

In Australia a branch of a vine exhibiting different characteristics from the expected is called a 'sport'. Back in 1980 the Cleggett family - who have been growing Cabernet Sauvignon since 1911 - found a vine with a 'sport' of bronze-coloured grapes. They propagated this from cuttings and after a few years made a wine called 'Malian'. Ten years later one of the Malian vines produced a 'sport' of golden white Cabernet Sauvignon grapes. They propagated this as well and registered the name as 'Shalistin'. Analysis has shown that both of these have the same DNA as the Cabernet Sauvignon that they were bred from, which means you can now try a white Cabernet Sauvignon. When I tasted it I found it to be at its best when cool rather than cold, when its Cabernet characteristics could be better tasted, along with fruity overtones and a strong bouquet. Unusual and interesting.

Available Wines from OZ, Enniscorthy and Supervalu Carlow. About €14.