Determining viticultural climate

Not the most eye-popping headline, I agree, but this been on my mind quite a lot recently - and that's what comes with spending lots of time with MW students. That and stained teeth.

When identifying wines blind, one of the most critical factors is determining what type of climate is most likely. This should be relatively straightforward because there is a concrete relationship the temperature of a region and the levels of acid, alcohol and fruit ripeness in a wine. Of course, those structural elements can be mitigated by lots of other factors, but in most cases, you would expect a wine's style to reflect the climate of its origin, especially when dealing with classic wines.

For simplicity's sake, it makes sense to establish three main climatic types: cool, moderate and hot. You could perhaps include cold for regions such as England or Tasmania - though it is usually easier to keep things simple.

Certain regions seem relatively easy to define, as follows:

  • Mosel is cool, with sharp fruit, high acid and low alcohol to reflect that (with the proviso that sweeter Rieslings have low alcohol due to arrested fermentation)
  • Bordeaux is moderate, with generally high acid, yet alcohol that ranges from moderate to high (possibly with chaptalisation as a modifying factor) and fruit that ranges from underripe to overripe. 
  • Barossa is hot, with very ripe fruit and high alcohol - though because acid is usually added, it would usually be incorrect to say its wines are low in acidity

However, almost everywhere else has a more complicated story. One of the most frequently repeated phrases that MW students use when identifying climate is 'warm with cooling influence', which can be useful but tends to make everywhere sound the same. It can apply to Mendoza and Clare Valley (altitude), some Napa AVAs (fog), coastal Chile (sea influence), much of Austria (continentality) - virtually anywhere you look there is the opportunity to find something which allows you to complicate the climate of a viticultural region. 

So is it even possible to summarise a viticultural climate in the way that wine students need to when identifying the origin of a wine?

Well, it's no good asking winemakers to define their climate because none of them will admit to having a warm climate, even if they're standing in shorts and a t-shirt in the middle of southern Spain. Official classification systems such as heat degree days or mean January/July temperature (depending on which hemisphere the vines are in) can be useful but can rarely be applied to all regions around the world.because they can never factor in all the variables that might have an influence on a region's climate. Whereas WSET literature can be too simplified - although this revision list of WSET diploma climates might prove useful as a reference.

When immersed in the nuances of blind tasting, it's easy to forget that there wine often doesn't provide answers that are definitely right and wrong. As for exams, however ...