Tag Archives: Temperature

Hot – or too hot?

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harvest 2017It’s difficult to believe as I look out of my window in cool and rainy Bristol, that, across much of southern Europe at the moment, there is a heatwave and a drought.  Daytime temperatures there have reached the mid 40s (over 110˚F) for several days in a row, with nights remaining over 30˚ (86˚F) and many places have seen no rain for months.  It may be fine for the tourists (some of them, anyway – I’d find it too hot) but, how about the locals trying to work – or, indeed, the crops?

Vines need both warmth and sunshine to thrive and produce good ripe grapes for wine but, when, as now, conditions get too hot, one of 2 things happen: if there’s plenty of water for irrigation (and local rules allow its use), the combination of great heat and water cause the grapes to swell quickly and rush to ripeness, gaining high levels of sugar (and so high potential alcohol) but not much flavour – that comes from long, slow ripening.  Also, without cooler nights, the acidity that is crucial to making a refreshing wine will drop sharply.  The result: poor quality ‘jug’ wines appealing only to those seeking bargain price quaffing.

When drought conditions accompany a heatwave, as we’re seeing now in southern Europe, or where irrigation is banned, things are very different.  Without water, the vines will begin to shut down in order to protect themselves; the grapes will shrivel and fall off and the harvest will be much reduced.  Producers then need to decide quickly: pick straight away and salvage some of the crop or wait and hope that September will produce cooler temperatures, rain and better prospects.   That is the choice being faced by many now.  When similar extreme conditions occurred in 2003, most chose to pick in August rather than wait.  A few good wines were made, but many were unattractive with baked or dried fruit flavours and some normally long-lasting wines faded quickly. 

But, although 2003 and 2017 are truly exceptional, growers right across Europe are reporting that, even in ‘normal’ years, they are harvesting 2 or 3 weeks earlier than their parents did and picking riper grapes.  And varieties that once only grew in certain places are now thriving in regions that were previously thought too cool. 

Something is certainly happening to the world’s weather.  The climate is changing and all of us, not just the winemakers will need to adjust to it.