The wet winters and warm summers created by a changing climate in Bordeaux are the secret to great vintages – until the water runs out, writes our student Andrew Wood (2017, Biology, DPhil Biology) in a widely reported new research study.
Andrew and his colleagues took high-resolution weather data and compared it to wine critic scores from the Bordeaux region in Southern France from 1950-2000. They also looked at wine quality at the regional (how did Bordeaux wine vary in quality from year to year overall?) and local level (how did wine vary year to year for specific “appellations d’origine contrôlées”, or AOCs, in the area). Taking this data, they created computer models that tested how weather factors such as temperature, rainfall, and the length of seasons affected the critics’ assessments.
The link between wine quality and weather is well known, but Andrew’s study is one of the first to also investigate the impact of climate during the non-growing season in the winter, when the grape vines are dormant. They found that weather throughout the year mattered for the final product, rather than just during the spring and summer. Wet winters, followed by warm and wet springs, hot and dry summers, and cool and dry autumns gave the best results. This pattern of weather has become more common in Bordeaux since 1950 as a result of climate change, with average wine scores also increasing over the period (although this could also be down to rising and improving use of technology or winemaking techniques).
“With climate change generally, we are seeing a trend across the world that with greater warming, wines are getting stronger,” said Andrew Wood.
“People generally prefer stronger wines which age for longer and give you richer, more intense flavours, higher sweetness, and lower acidity.”
While climate change thus far has produced more palatable wines from the region, Andrew is quick to point out that it remains a looming existential threat to viticulture.
“The problem in scenarios where it gets really hot is water: if plants don’t have enough, they eventually fail, and when they fail, you lose everything.”
Andrew’s paper, ‘Seasonal Climate Impacts Wine Quality in Bordeaux’ has been published in iScience.
Andrew Wood. Photo: Jack Evans