Expertise

The effect of global warming on Burgundy

So far, I think the effect of global warming has been positive for Burgundy.

The Effect Of Global Warming On Burgundy
Vineyards outside Pernand-Vergelesses in the Côte de Beaune, Burgundy

Chardonnay

Picking chardonnay earlier, often at the end of August, as against say mid September in around 2000 has resulted in many successful vintages. 2014 was one of the best of the last 20 years. Some are a little richer than previously and the odd one like 2013 has still been picked in October. Only a few have been close to overripe (2003, 2009, 2015). Many wines are at 13% or 13.5% these days which is balanced. Before, lighter wines may well have been chaptalised. In the 1970s,1980s and 1990s there were many vintages made from slightly unripe grapes as autumn rains forced picking as rot and other fungal diseases threatened to, or had, developed. To make good wines you need ripe grapes.

However, we may soon arrive at a tipping point if the global warming continues. The map of where the best wines will come from may have to be redrawn. It was based on precocity. The best sites were those that ripened their grapes first, before the autumn rains. Most of the great vineyards were those around or below 300m and often facing south-east, which maximises ripening. Now, some vineyards which turn a little towards the north, like Les Autés in Auxey-Duresses, are producing wines with a lovely sparkle of freshness.

Conversely in Chablis, to keep the minerality intact the south-facing Mont de Milieu is rushed to be picked very early in the vintage, as is the grand cru Vaudésir in its hot enclosed valley. We are now seeing some of the higher villages –such as Vergisson in the Mâconnais, Saint-Romain and the Hautes Côtes de Nuits in the Côte d'Or, and Chiroubles in Beaujolais –regularly producing wines with that extra spark of freshness. For the cool enclosed valley of Saint-Aubin, which never used to ripen every year, its time has come.

Has the time now arrived for Saint-Aubin?
Has the time now arrived for Saint-Aubin?

Pinot Noir

Red wines need a little more sunshine and heat to ripen than white wines so red Burgundy is currently thriving. Burgundy is the most northerly of Europe's major regions for fine red wines. In the 1950s and 1960s, harvests took place at the end of September and often in October so many never ripened properly. Even in the 1970s and 1980s, the success rate was three or four vintages in a decade. This decade, 2012, 2015, 2016, 2017, 2018 and possibly 2019 have all been lovely. 2015, 2016 and 2018 are potentially great vintages.

What is striking since about 2015 is how Pommard, Aloxe-Corton and the southern crus of Nuits-Saint-Georges have been changed. Planted on cool clay soil, they often lacked full maturity of the tannins which remained a bit dry and scratchy. Now they have sweet and rich palates.

Generally, the best wines come from the middle of the slope, where good drainage, a perfect mix of clay and limestone soils, sloping vineyards angled to the south-east intercept more sun and minimise frost risk, allowing cool air to drain away. This is where all the premiers and grands crus are situated.

However, in very warm years with less rain there is some good, ripe red Bourgogne. Often planted at the bottom of the slope on flat, wet clay soils with a fatal combination of lower ripening ability (because clay soils are cold and delay ripening) but more yield (because clay soils are more vigorous), in normal years the Bourgogne does not ripen. Clay also produces more tannic wines. When the tannins are green, astringent and plentiful, this makes for a horrid wine.

But in dry and very warm years, clay comes into its own. It warms up, the hot years ripen a bigger crop and its water-holding capacity is beneficial in dry years. There is an upside to global warming. This was even true in 2018 where yields were high.

Spring Frost

One problem that is becoming greater is the risk of spring frosts.

Damage caused by spring frost
Damage caused by spring frost

Historically, Burgundians said there was a risk of frost until the Saints Glaces (the Ice Saints days, of 11th, 12th and 13th May) passed. Today, warm winters are causing budbreak to occur up to a month earlier. This year (2020) it was 20th March. This week, vignerons in the Mâconnais and Côte d'Or have been lighting bougies, a type of large wax candle, to keep the frost danger at bay. Thus there is now another month where the vines are in danger.

Many are pruning very late, finishing the end of March. Such late pruning can delay budburst by a week. This has been long known, as in the saying:

Taille tôt, taille tard
Rien ne vaut la taille de mars

The problem is organising the work which used to occur over all the winter months over a shorter more concentrated period. Others are considering moving the main fruiting wire up from 40cm. This may also increase the shadow between the rows and slow ripening –something that used to be avoided!

Rootstock Suitability

Jean-Marc and Anne-Marie Vincent
Jean-Marc and Anne-Marie Vincent

One victim of the changing climate is a hitherto well-renowned rootstock which was used for some of the best vineyards in Burgundy, 161-49. It does not like the increasing alternance of wet then dry conditions and is dying.

One of our best growers, Jean-Marc Vincent in Santenay, replanted his Beaurepaire in 2004 and his Passetemps in 2009 with 161-49. He now has to rip them up and replant. He will replant at a higher density (about 14,000 vines/ha, up from 10,000 currently) with good-quality clones and so an improvement will occur over time.

The Future

If global warming continues over the next two decades, then Burgundy will change and will, like everywhere else, need to adapt with more radical solutions.

Chardonnay

According to some, chardonnay is adapting well to the warmer climate. Historically in Burgundy, one counted 100 days from flowering to harvest. Now it can be harvested after about 90. Choosing later-ripening clones and planting densely, up from the current 10,000 vines/ha to over 14,000 and even higher, would help preserve acidity.

However, if it gets warmer and alcohol continues to increase and acidity diminish, it may be time to allow chardonnay to be blended with other varieties. Aligoté is often found in grand cru vineyards and is lighter, fresher and more acidic. A secret weapon could be the very acidic petit meslier grape from Champagne.

Pinot Noir

Red grapes react less well to extreme heat than white grapes. The main reason why alcohol in reds is rising is not because winemakers want it to, but because flavour and tannin ripeness lag behind sugar ripeness.

While the accumulation of sugar more or less follows photosynthesis levels, tannin ripeness is made by the grape from the sugars and needs more time. The dilemma for the winemaker is if you pick too early the grapes taste green and have harsh tannins. Pick too late and the alcohol can rise.

Generally, it is considered that it is overall more successful to pick with more alcohol and sweet tannins than the other way around. This phenomenon has been present in the new world for a long time. Now it is striking Europe, and not just Burgundy. In Bordeaux, the hot years of 2009 and 2010 some of the merlot-based wines of the right bank were often 15%.

In the vineyard, probably the best solution is to use rootstocks which delay maturity and as for white wines, plant later-ripening clones and move to higher density.

Picking grapes early to control alcohol can lead to under-developed tannins and un-balanced wines
Picking grapes early to control alcohol can lead to under-developed tannins and un-balanced wines

In the Laboratory

Scientists are trying to find yeasts that produce less alcohol from the sugar in the must. Currently about 17g of sugar produces 1% alcohol. So far, the yeasts they have found that produce less alcohol have produced a lot of volatile acidity (vinegary aromas).

Removing alcohol, adding water

Reverse osmosis is being used to remove alcohol from wine quite successfully. It is legal to add water in some countries. This seems sensible to me. If the wine is too strong then dilute it. It seems no worse than what Europe did before global warming, when lack of ripeness was a problem, which was to add sugar, or Chaptalise, after Henri Chaptal the French scientist who invented the technique. It just had a posh name!

Read Toby's guide to Burgundy

Toby Morrhall

Society Buyer

Toby Morrhall

Toby has been a Wine Society buyer since 1992, and covers Burgundy, Chile, Argentina and Uruguay.

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