theBad news for Spanish sherry. The micro-organisms responsible for the biological maturation of sherry will be virtually impossible by mid-century due to the expected rise in temperature caused by climate change.
This is the outcome of a study by the Polytechnic University of Madrid. It also concludes that Spanish sherry wines must adapt to global warming in order to survive.
The study followed the microorganisms involved for several years. It analysed the effect of climate change on the biological maturation of sherry wines. Researchers followed the thermal behaviour of a winery to then develop a computer model for energy simulation of the building. With this, they carried out simulations of the outdoor climate for future climate change scenarios proposed by the UN Intergovernmental Panel on Climate Change (IPCC).
Temperature rise in Jerez region
One of the authors the study, Professor Fernando Ruiz, warned that by mid-century, the average outdoor temperature in the Jerez region will rise by 2.3°C. Moreover, an increase will be even more pronounced during summer, when increases of up to 4ºC are expected. ‘As a result, the temperature in the ripening room will exceed the limits of thermal comfort for the activity of micro-organisms’, which ‘jeopardises the production process in its current model,’ he stressed.
Velo de flor
This organic ageing under ‘the layer of flor’, the typical yeast, is what gives Jerez wines their unique character. However, it is precisely this which is now at risk. This ‘velo de flor’ is a biological film composed of a mixture of micro-organisms that protects the wine from the oxidising effects of air. Thus, the evolution or ageing of the wine is not oxidative but biological. The continuous action of this ‘flor is reflected in the appearance of different and particular organoleptic characteristics that make Jerez wines unique.
This biological ageing requires very sensitive and restrictive environmental conditions, with an abundant presence of oxygen. Therefore, ageing traditionally takes place in unique, sometimes more than 100-year-old buildings known as ‘Bodegas Catedral’. Their simple but effective architectural style provide the specific ecological conditions for organic wine ageing. Consequently, they do not have the need for a mechanical air conditioning system. Thus, they are a clear example of sustainable buildings.
Threat to wine tourism
The study shows how precisely this traditional production process, which is so strongly influenced by the climatic conditions of the environment, could be affected by global warming. This could threaten the continuity of one of the world’s most important wine tourism destinations. The researchers stress that, after centuries of success, the rise in temperature due to climate change could affect the effectiveness of the cathedral cellars, jeopardising biological ageing by exceeding the limits of activity of the microorganisms involved. A key conclusion of the study is the need to develop a plan of action. This will be necessary to maintain the production and characteristics of sherry wine cellars.
Also read: The art of Spanish sherry from Jerez