With Spring bursting at its seems this year the saying “to everything there is a season” (Ecclesiastes 3:1) comes to mind. However the seasons seem to slip a little each year – the average harvest dates recorded in Bordeaux have been 3 – 4 weeks earlier than previously and each season brings new obstacles to deal with. Bernard Seguin, researching for INRA (National Institute for Scientific Agronomic Research) has said that in addition “the rise in temperatures has produced sweeter grapes with more alcoholic potential and less acidity at harvest time” and this was certainly the case for the 2010 vintage.
However over the centuries Bordeaux has seen many weather extremes come and go – and adapted to them. Jean-Michel Chevet, Sébastien Lecocq and Michael Visser (INRA), have come up with some interesting results in their study of the climate change in the Médoc, registered between 1800 and 2009. The coldest growing season was in 1925, with average temperature barely above 15ºC and the hottest season was in 2003 (average temperature slightly above 20ºC). The overall mean growing season temperature during 1896-2009 was 17.4ºC.
1898 was the driest year: between October 1897 and September 1898 only 472mm of rainfall was measured in Bordeaux. In 1977, the wettest year, there was almost three times more rainfall (between October 1976 and September 1977 cumulated rainfall amounted to 1,360.5mm). The overall mean October-September cumulated rainfall was 865.8mm.
Over the 200 year period the researchers found that temperatures declined from the beginning of the observation period until roughly 1925, and then found upward trend in temperatures starting around 1985 until the end of the period.
One of the findings in their research shows that improved vineyard management techniques can reduce the impact of climate on yields:
“We see that the effect of climate on yields has become smaller and smaller over time . . . A natural explanation is that over time wine-growers have increased their control on production levels through all sorts of techniques. In the 19th and beginning of 20th century the vineyards in Pauillac were infected by many climate-related diseases (powdery mildew, different types of grapevine moth), and the natural fertilizers used at the time were not that effective. However, since the 20th century new and more efficient sorts of natural fertilizers were employed and better care was taken of the vineyards. Synthetic pesticides were employed on a massive scale since the 1960s . . . and the cloning of vines which started early in the 1970s rendered vineyards more weather-resistant.. Finally, starting around 1990, yields were deliberately reduced by the wine growers through fruit thinning in July (green harvesting.) in order to obtain higher quality. This may explain why in more recent periods the impact of temperature is smaller.”
So Bordeaux has learnt to overcome a lot of what the climate throws at it. An important point is that although the researchers had access to the records of a First Growth in Pauillac spanning 200 years with which to conduct their research . . . they do not know to which grape variety the onsets of the three phenological stages refer. We know the grape varieties grown nowadays but in the 19th century Bordeaux used a variety of grapes that are now long forgotten. Gros Verdot, for example had its peak in the 19th century and died out, and then was allegedly rescued by Château Lafite who used it 1868 for its blends (see Long Lost Bordeaux Grape Varieties). We also know that the now well known Merlot and Cabernet Sauvignon were introduced to Bordeaux in the mid 1850s (see Chateau d’Armailhac, Mouton and Merlot and Chateau Brane Cantenac, Mouton Rothschild and the Baron). Obviously as the weather over the centuries has changed in Bordeaux so have the grape varieties. Doubtless – in time – they will continue to do so (see Syrah in Bordeaux? and Bordeaux and Malbec – a Contender for Climate Change?).
Bordeaux also used another technique to improve their wines in times past – that of Hermitage. Hermitaged Bordeaux refers to the practice of adding wines to the Bordeaux blend particularly in a poor vintage (this also happened in Burgundy). Hermitage takes its name from one of the areas that the wines added to the Bordeaux blend comes from – the most famous of all the northern Rhône appellations: Hermitage. However the Rhone was not the only region that Bordeaux took wines from – early in the 1800s records show that that wines from Bénicarlo in Valencia, north east Spain were added to the Bordeaux blend. One source from 1824 (Henry Christmas, George Augustus Frederick) states that each hogshead of Bordeaux had 3 or 4 gallons of Alicante or Bénicarlo added to it. This was called tracait a la anglaise (the English treatment). Cyrus Redding (1833) says that Claret was a mix of Bordeaux and Bénicarlo. (See Bordeaux from Valencia).
Perhaps we will see (or my children will) the introduction of grapes from hotter climes to Bordeaux should the climate continue to alter. The claret that some people are lucky enough to drink from the 1800s is definitely a different Claret compared to that of today . . . but it is still Claret. Should Bordeaux alter its permitted grape varieties in the future the wine will also be Claret . . . the grapes will be grown on Bordeaux terroir, with Bordeaux wine maker’s techniques and in a Bordeaux style.