Now that European wine authorities have decided to authorise the use of oak chips and a host of other winemaking techniques previously derided by many as irremediably New World, it is worth considering the likely effects on the wines we are likely to be offered over the next few years.
For years many of Europe's more traditional winemakers and wine drinkers were fiercely opposed to the use of oak in winemaking in any form other than a fully finished barrel but, much to everyone's surprise, just before Christmas last year the Italians forced through a change in the European Union rules allowing winemakers to use what are called 'oak alternatives'. These include fragments of oak, called oak chips in English and copeaux in French, as well as pieces of oak as large as barrel staves, called barrel inserts or, more prosaically, 'planks in tanks'. They are generally added to large volumes of wine before fermentation although they may remain suspended in the wine, in permeable sacks in the case of oak chips, sort of giant teabags, for some time afterwards.
Oak does two things to wine, or at least two main things that are so far understood. The more important one is that it helps stabilise it and smoothes its texture, encouraging the phenolics in wine, especially tannins, to polymerise and create a much more flattering 'mouthfeel'. It can also deepen flavour by encouraging the formation of complex compounds of flavours derived not just from grapes and fermentation but also from oak, only sometimes adding an overtly oaky taste. This applies as much to white wine as to red and is one of the reasons why barrel-fermented whites can taste much rounder and more supple than those made without any oak influence.
Oak is the wood with the greatest natural affinity with wine – the flavours seem to harmonise particularly well – and oak barrels have been used for making and storing wine since classical times. But barrels are expensive to make; making, using and maintaining barrels is also time-, space- and labour-intensive. Using a new barrel can easily add several dollars a bottle to production costs. And perhaps even more significantly, barrels need very careful maintenance. The wine inside them has to be constantly replenished because of evaporation. It's awkward to move wine between barrels as has to be done when separating it from the lees, and barrels can all too easily be ruined by moulds and bacteria if they are left empty for any length of time.
Perhaps the most surprising aspect of oak alternatives (which are, strictly, alternatives to barrels rather than to oak itself) is that it has taken the wine industry such a long time to get round to using them. They are so obviously very much cheaper than barrels and allow skilled winemakers arguably even more flexibility about how long they keep the wine in contact with oak. Easier, quicker and very much cheaper to yank a plank out of a tank than to empty a cellarful of barrels…
But until now oak chips have been used almost exclusively for cheap wines, too many of them both cheap and nasty. The first time I became overtly aware that oak chips had been used was back in the early 1990s when the character of Bulgarian Cabernet Sauvignon, which had been one of great bargain reds available in Britain, full of vibrant fruit, underwent a very obvious change. The fruit seemed to disappear under a oil slick of heavy-handed sweet, coarse oakiness. Eastern Europe was in such turmoil in the early 1990s that there were probably many other factors at play there but ever since tasting this generation of wines I have been on the lookout for such overtly oaky flavours and reckon I have found them on cheaper reds from many countries outside Europe.
Within Europe, or at least within its heartland the European Union, the use of oak chips has officially been strictly forbidden. They have been seen as an ersatz option that flies in the face of the noble tradition of making and using proper barrels. But now that this prohibition has been abandoned, on the advice of scientists advising the OIV, the international wine organisation, and the detail of the new permissions are being hotly debated in airless offices in Brussels and Paris, it is highly likely that oak chips, inner staves and the other 'New World winemaking techniques given an EU green light last December, will officially be allowed throughout Europe in time for the 2006 vintage.
The detail being discussed is exactly what sort of oak may be used and how. There is as much variation in the quality and characteristics of oak alternatives as there is of barrels. Winemakers can choose from different provenances, different seasoning regimes, different toasts and can even choose oak chips that have been impregnated with lactic acid bacteria to help provoke the second, 'softening' malo-lactic fermentation.
And there is another very important question to be decided: how these wines should be labelled. At present, it is possible sometimes to discern on the back labels of non European wines when oak alternatives have been used: generally, if oak influence is claimed but there is no mention of the b-word.
The other 'New World' techniques no longer prohibited in Europe, incidentally, include use of ascorbic acid to prevent grape juice oxidising before fermentation; charcoal to remove nasty flavours or colour from red wines and juice (it was already allowed for white wines and used widely to produce such products as pale cream sherry); the use of mannoproteins and dimethyl dicarbonate to stabilise wine, and vegetable proteins to fine it.
What has changed is that more and more scientists charged with analysing these 'non-European' techniques have become convinced of their merits. And indeed there is a small but growing faction within the world of wine technology which argues that a combination of oak alternatives and micro-oxygenation, another new technique that involves bubbling tiny amounts of oxygen through embryonic wine in order to achieve similar softening and deepening effects, may even be just as effective for fine wine as ageing in the noble oak barrel.
For the moment few wine producers are prepared to raise their heads above the parapet and admit openly that they use and approve of oak alternatives, and even fewer producers of high-end wine are willing to risk their reputations by admitting to using a cheaper, newer technique without anything like universal approval. But I suspect this will gradually evolve into a more open and fascinating debate.
The world's leading coopers, those who until now have made fortunes supplying winemakers with millions of hand-crafted barrels made from French, American and, increasingly, eastern European oak, have quietly been investing in researching and developing their own oak alternatives. This is surely a sign that they recognise there is a healthy commercial future for oak chips and inner staves.
What is a worry, however, is the extent to which this globalisation of winemaking techniques may led to a globalisation of wine styles, at least at the bottom end of the wine market. Until now there has been a very distinct difference between basic European table wine on the one hand and the cheaper varietals of California, Australia and South Africa on the other – with the differences between these last three eroding over time. Will they all eventually end up tasting the same wherever on the globe they were grown?