Brandies in France under the threat of climate change: issues and ways ahead

Production, maturation and even style of brandies are potentially affected by climate change in unsuspected ways. Both in the vineyard and cellar, viticulturalists and winemakers have now to adapt their methods and processes to ensure quality remains up to standards. Through the example of brandies in France these recent changes are reviewed.

Climate change is here to stay, and also affects grapes destined to be distilled.

A proven fact is that climate change in France has affected vineyards all over the French territory. This is also verified in the Cognac region. Two weather stations, one in Cognac and the other in Saintes, 30 kilometers west of Cognac and 120 kilometers north of Bordeaux, have registered over the past 30 years a temperature increase of 0,8ºC and 1ºC respectively. Along with it, the number of days with registered temperatures over 35ºC has also increased and the number of days with frost in March and April has decreased considerably, going from 12% during the period 1968 to 1987 to only 6% in the 1988 – 2007 time span. Average rainfall has slightly increased by 2% over the past 30 years. Overall, the Cognac region has changed from a cool climate region to a temperate climate region from 1980 onwards. In extreme years like 2003, the climate can even be considered as warm.

Consequences of climate change in the vineyard.

Changes are recorded in the way the grapes mature. An increase of 1,5ºC in the mean temperature during the growing season makes that harvest takes place 15 days earlier than expected. This early harvest in turn increases the temperature during the ripening period by 2ºC. In total, the global warming that the grape endures is a total of 3,5ºC during the growing cycle. This has a deep impact on the grapes:

• an acceleration of sugar accumulation in the berry, which translates itself into an increase of the alcoholic degree;
• the heightening of malic acid degradation which involves a decrease in total acidity present in the berry: it is generally considered that an increase of 1ºC results in a loss of acidity of the juice at harvest of 1 g/l.

Jean-Pascal Goutouly , research engineer at the Institut National de la Recherche Agronomique – INRA (the French National Agriculture Research Institute) confirms that in brandy producing regions, harvest takes place two to three weeks earlier than in the 1970s and that average temperature during the growing season has increased by 1ºC in less than a century. This has consequences on the grapes: acidity is now lower and the alcohol degree higher, which is the contrary to what a wine for brandy needs to be. Double distillation needs wines low in alcohol and high in acid.

Moreover, extreme weather events are more common than ever, with severe consequences. In 2017, vineyards in the South West have been strongly affected by late frosts, making that harvest loss is estimated at around 31% (Source: Agreste). This has commercial impacts on the different markets where competition is fierce and where a loss of market share one year may require many more years to recover.

As secondary consequences, the increase of the CO2 content in the air will potentially have an impact on vine photosynthesis and biomass production (leaves and fruit). However, vine adaptation to the above-mentioned elements is still difficult to evaluate. Besides, the impact of new pests and diseases will have to be monitored.

The impact of climate change in the cellar: an issue that winemakers are taken more and more seriously.

Since any type of sulfur dioxide (SO2) addition is forbidden in brandy production in France, the wine has to have a high acidity to help prevent the diffusion of unwanted microbes at every step of production. In any other wine production area, SO2 plays a prominent role, acting as antioxidant, antiseptic and anti-oxidasic. When SO2 cannot be used and wines have a low acidity and a high alcohol, winemakers have to considerably increase their efforts to keep the wines fresh and protected.

In the case of Armagnac for instance, grapes used to produce wines that are tart, low in alcohol and high in acidity. Wines between 8º and 9º are considered ideal for continuous distillation. Charentaise-type pot stills are modern, large-scale alembics that can distill wines with elevated alcohol levels without problem. Yet wines of more than 10º - which are found more often than not today - are problematic for the traditional alambic because they heat too quickly and do not entirely condense as they leave the still. This causes flow problems. The spirit spurts out and part of the distillation ultimately is lost as a vapor.

Folle Blanche, Bacco and Ugni Blanc normally arrive between 8º and 10º. Colombard however, tends to reach 10,5% or 11%, which might require the distiller to lessen the wine’s degree by adding water – something that will dilute some flavor but ultimately lead to a smoother distillation. The resulting spirit has less overwhelming fruit and inherent aromatics.

Solutions in the vineyard: from short term actions to long term commitment to change.

Canopy management is the first natural idea that pops up to mind when a viticulturalist thinks about ways to combat climate change. It is relatively easy to train / prune differently, leaving more leaves to protect the grapes from sunburn, to keep acidity in the grapes and slow ripening.

Changes in row orientation are another way to handle climate change but this is only valid for new vineyards, which can change from a north / south orientation to a north-east/ south-east orientation so that the grapes do not receive so much sun in the afternoon. Plantings can also be made on north facing slopes so that grapes receive less sun during the growing season. Cover crops between the rows can be limited so that water and nitrogen are kept in the soils for the vines.

A long-term work with clones can also be made, using clones that make grapes less rich in sugar and maintain a high acidity level; since 2008, the INRA works with 700 different clones to determine which ones will allow to make great quality cognac in the future; in Cognac, the number of clones of Ugni Blanc currently existing will have to be explored further and potential adaptation possibilities will have to be analyzed.

New grape varieties are also tested: even though ugni blanc grape variety reigns supreme with around 98% of all surface planted in Cognac, trouble is that now ugni blanc is harvested with 11% abv, against 8% a few years ago. The monbadon grape variety, a natural crossing between folle blanche and the ugni blanc grape varieties could be a way forward. It has the advantages of offering high yields and low acid level (between 6º and 8º). In the past, this grape variety was not even considered, because it was too sensitive to fungal diseases. But now with higher temperatures and better training and pruning systems, it is under investigation. An experiment has been launched in 2013 by the Conservatoire du Vignoble Charentais (Vine Conservatory of Charentes). First grapes will be harvested this year and the first spirit will be produced in 2018. Then four to five more years will be needed to have a proper assessment of the real potential of this recovered variety.

Night harvests and harvest refrigeration before crushing will be more and more common. Since the use of any SO2 is forbidden by law, grapes will have to be harvested at night or refrigerated before processing in order to contain any microbial attack.

In all cases, the impact on the typicity of the final product should be considered.

Solutions in the cellar will have to be coupled with those in the vineyard.

Since acidities tend to be lower in the wines, they must be protected in the cellar at all times. For instance, Tariquet, one of the biggest producers in the Armagnac region, keeps its wines cold using low temperatures.

During maturation, the ageing process is both physical and chemical and it needs time to produce elegant spirits. After 10 or 11 years in wood, the spirit gets more complex and harmonious. It mellows and a hint of vanilla starts to creep in. This slow ageing needs specific conditions. If the chai (cellar) is especially humid, then the loss of alcoholic strength will be much greater, whereas an unusually dry warehouse induces unnaturally fast evaporation of what remains a strong spirit. A brandy left for twenty years in an especially dry chai will retain the youthfulness of a ten-year-old. The same period spent by brandy in an unusually damp chai will add five years to its physical age. Increasing temperatures make that this slow exchange between the spirit and the wood through the impact of oxygen might be disrupted. It is precisely the expansion in summer months and the contraction of the spirit during cool months, allowing the controlled entry of oxygen in the barrels that make a fine and elegant brandy. Any attempt to introduce temperature control devices in a chai will alter the natural conditions that the brandy requires to mature harmoniously. And this is all the more relevant since scientists have now perceived that the controlled evaporation involved in the maturation process is a continuation, albeit at a much slower rate, of the processes begun in the alembic. The wood allows the oxygen to seep steadily through to the spirit, and its metallic elements act as catalysts. This slow oxidation ensures that the aromatic elements in the spirit are preserved, although they would be lost in a speedier chemical reaction.

Overall, like any other wine producing region, Cognac and Armagnac not only have to fight climate change in the traditional ways other regions do, but they have the added complexity of maturing and ageing the spirit so that elegance and a consistent product can be offered year after year. For those keen on following the evolution of brandy styles over time, I encourage a vertical tasting of old and recent brandies in order for you to make your own opinion and pick up the style you prefer!