Wine opinion: why some aromas are better left out of the bouquet
The recent isolation of certain bacteria and yeast as responsible for terroir - the evocation of a sense of place in the flavour of a wine - is another apparent triumph for the application of science to the art of winemaking.
It is tempting to believe that modern winemaking techniques and an advanced supply chain mean that it is difficult to buy bad wine these days. But while science advances, it is not clear that human nature does.
Unscrupulous winemakers still don't clean their equipment properly, and use bad fruit. So, as the saying goes, "rubbish in, rubbish out." But this wine still has to be sold.
Cork taint is the most famous of wine faults, but research into producing cleaner corks has reduced the incidence of this dramatically in the past decade. Using other closures eliminates the problem altogether. But as Penfolds' chief winemaker Peter Gago once told me, the condition of the wine becomes a great record of its storage.
It takes a lot of effort to ensure that wine stays at optimum temperature during transit and storage, and it's not an effort that everyone in the wine industry is willing to make.
Banana, a flavour I most often find in generic white wines, most recently in glasses of chardonnay from Australia and Italy, can be the result of dirty equipment in the winery.
It's also a possible product of cold fermentation, the process by which winemakers in warmer countries try to mimic the ambient temperatures of wine-producing regions such as Alsace or Germany. If that process goes wrong, the yeast can produce hydrogen sulphide, also known as sewer gas. Lovely.
The banana flavour is one that is sought out by Japanese sake makers, but I doubt it's a flavour we want in our wine.
Alsace riesling can have this flavour, but that means it is being drunk too early, and would have developed some spicy characteristics if left.
Even well-intentioned winemakers using hand-picked fruit can't guarantee perfection in every bottle. I was recently lucky enough to attend a wine dinner hosted by Bordeaux Chateau Malartic-Lâgravière.
An evening of good wines was interrupted by the opening of a bottle containing the yeast Brett, or Brettanomyces bruxellensis, which imparts a flavour called saddle leather, or even less appetisingly, horse's sweat. This is an interesting fault - it used to be so common in Bordeaux that winemakers trying to imitate the style would make wine with the flavour.
The yeast was identified more than 100 years ago, and scientific advances have reduced its presence. But, so far, it remains ineradicable.
I also recently tried a glass of rosé from 2010. Although the bar owner refused to believe me, this wine was over the hill. It was lifeless, dull and flavourless. I had tried it because I was surprised to see a rosé that age on a wine list. There are a few rosés made for ageing, some successfully, others less so.
I once tried one that was said to take its tannins from the stalks it was pressed with, and had a flavour of acacia. That leaf is the predominant diet of giraffes and, like bananas, is not a sought after flavour in wine. The flavour of acacia may not be a technical fault in a wine, but it makes that rosé a bad example of the type.
Surely no restaurant group or supermarket buyer would voluntarily put rubbish on the shelves. Voluntarily is the key word here. If you want to sell premium brands, you're going to be selling the generic wine, bananas and all.
