Wine Stats

Figures about the Wine World

Home » Articles posted by Tony (Page 5)

Growing Degree Days in Marlborough, New Zealand

Of the many environmental factors which affect the productivity and quality of grape vines and their fruit, arguably the single most important variable is temperature during the growing season.  Photosynthesis in Vitis vinifera is temperature dependant, and this in turn affects vegetative and reproductive growth.  Different cultivars of V. vinifera have differing temperature tolerances, which largely drives the differing assemblages of cultivars observed in different wine growing regions.

Several measures have been proposed which seek to summarise the temperature records over a growing season into a single numerical value. These include the Huglin Index, Biologically Effective Degree Days (BEDD) and Growing Degree Days (GDD).  Of these GDD, defined as \sum((Tmax + Tmin) / 2) – 10°C), is probably the most widely used and has proven useful in helping to understand differences in wine growing conditions in different parts of the world.

Marlborough-vineyard-GDD-maTo fully interpret GDD data for a particular wine growing region, it’s necessary to examine how these values change both in space and time.  The Marlborough Research Centre maintains weather stations at Blenheim in the Wairau Valley and at Dashwood in the Awatere Valley.  Temperature data from these two sites has been integrated with information from other weather stations by the New Zealand National Institute for Water and Atmospheric Research (NIWA).  This has allowed them to produce a grid of temperature data, which has been used to produce the GDD map.  This map shows the median GDD values based on data derived over a number of years.

The map shows the strong influence that topography has on growing season temperatures, with the elevated areas being markedly cooler.  Although on average the Awatere Valley is slightly cooler than the Wairau Valley, there is significant variation within each of these two subregions.

Marlborough-GDD-plotLooking at annual GDD figures at particular weather station(s) brings out the growing season temperature variations associated with particular vintages. Notable are the unusually high GDD values for 1997/98 and the very low values for 2011/12.  The former is probably the result of an El Niño Southern Oscillation (ENSO) event which caused New Zealand to experience an exceptionally hot summer.  By contrast, 2011/12 was described by Wine Marlborough as having a summer which “never really arrived”.

For 2012/13, growing season temperatures were significantly higher than the previous year.  Gapes harvested from Marlborough in 2013 totalled 251,680 tonnes, up from 188,649 tonnes in 2012.  Already being called an outstanding vintage by some winemakers, WineStats will be attending the London New Release Tasting to see if 2013 exhibits high quality as well as quantity.

Vineyard Area, Production and Wine Yields in Chablis’ AOPs

Chablis is an isolated wine region of northern France, arguably the most northerly region in Europe producing high quality, still table wine.  World-famous for its production of food-friendly dry white wines from Chardonnay grapes, it should display mouth-watering acidity, restrained fruit flavours and so-called mineral characteristics.  The region is divided into four Appellations d’Origine Protégée (AOPs), based on the perceived quality of the land for growing and ripening Chardonnay.

Area-Growth-by-AoPThe area of vineyards in Chablis has expanded enormously since 1970.  Then there were only 757 ha in production, but over the next 40 years this increased almost seven-fold to reach 5,043 ha in 2010.  By 1995, Chablis Grand Cru and Chablis Premier Cru were both at, or close to, their maximum delimited areas.  Additional growth since then has been of the less well-regarded Chablis and Petit Chablis AOPs.  The Chablis AOP had a production area of 3,318 ha in 2010.  Since the maximum limit for the Chablis AOP, as designated by the INAO, is 4,420 ha, there is still room for considerable future growth.  Similarly, Petit Chablis’ 2010 vineyard area of 843 ha still has some way to go before the INAO limit of 1,562 ha is reached.

Production-Growth-by-AoPThe increasing amount of grapes being grown in Chablis has allowed producers to ramp-up wine production.  In the early 1970s, total Chablis wine production was ca. 20,000 to 40,000 hl.  By 2006-2010 wine production had climbed to between 270,000 to 290,000 hl.  Prior to 1970, genuine Chablis (as opposed to, say, Gallo’s “Chablis” from California) was available to only a limited number of wine drinkers.  Now Chablis AOP and Petit Chablis AOP wines are produced in sufficient quantities to make them widely available in a variety of domestic and export markets.

Yields-by-AOCIn addition to increases in vineyard area and production, wine yield (expressed as hl/ha) has also shown a long-term upwards trend before levelling off at between ca. 50-60 hl/ha over the past 25 years.  Year-on-year climatic variations certainly play a role in determining the harvest size and complicating this picture, though perhaps not quite so much as might have been anticipated.  Following a series of poor harvests in 1977, 1978 and 1981, the Chablis region had a pretty good run until the heatwave vintage of 2003.

Although wine yield is but one of many factors influencing wine quality, it is often cited by wine critics and educationalists as being a critical one.  You might expect that within the Chablis region, wine yields within the AOPs would be arranged such that Chablis Grands Cru AOP would have the lowest yield and Petit Chablis AOP the highest.  Over the past quarter century Chablis Grands Cru AOP has indeed had the lowest wine yield, but there has been precious little difference between the wine yields of the Pemier Cru, Chablis and Petit Chablis AOPs.  Are producers of Petit Chablis AOP over-performing, or is wine yield not so relevant here? WineStats hasn’t been to sufficient Chablis tastings to have a view on this one.

WineStats would like to thank Cécile Mathiaud and Virginie Valcauda of the Bureau Interprofessionnel des Vins de Bourgogne (BIVB) for kindly supplying some of the data used in this posting.



Rias Baixas in Figures: Free Download

Rias Baixas is celebrating its 25th anniversary as a Denominación de Origen in 2013.  During this time it has undergone considerable growth and development, so now seems as good a time as any to take stock of its achievements.  The 5 page free downloadable PDF, Rias Baixas in Figures summarizes the readily available data to help explain the Rias Baixas story.

The Vineyards of Galicia, Northwest Spain

Wines from Galicia, Spain’s northwestern autonomous region, have been attracting welcome attention lately.  Albariños from Rias Baixas and Mencias from Ribeira Sacra are leading the charge and making their presence felt on restaurant lists outside of Spain.  Perhaps less known is the overall makeup and composition of Galicia’s vineyard arrangements, which play an important role in determining the styles, quantities and prices of wines from the region.

Galicia-area-pi-chart-2In 2012 Galicia had 26,233 ha of vineyards, all of which are used for the production of wine grapes.  Of this amount, vineyards in the five Denominaciones de Origen Protegidas (DOP) accounted for 9,689 ha or 37%.  There are three areas in Galicia with Indicaciones Geográficas Protegidas (IGP) status, but their total area amounts to a mere 20 ha.  Whereas regions such as Sicily are producing large quantities of IGP wine, you’re unlikely to see a Galician IGP wine in a supermarket anytime soon.  The remaining 63% of the Galician vineyard lack any geographical indication and are almost entirely used to produce wines which are consumed locally.

Galicia-Vineyard-size-distrThe bedrock geology of Galicia consists of Palaeozoic igneous and metamorpic rocks.  Subsequent tectonic activity and weathering have produced a rugged topography with many steep slopes and deep valleys. Along the coastline many of these valleys have been drowned producing inlets or rias.  Such topography means that in many areas mechanised farming is not possible, and labour costs farming terraced plots are high.  Individual plots are almost universally small, with the 2009 vineyard survey showing that 97% of Galicia’s 83,942 vineyard plots were <1 ha.  Producing grapes on such small plots creates something of a logistical nightmare for the bodegas and inevitably means that Galician wine producers lack economies of scale.

Galicia-DOs-areaOf the DOPs in Galicia, only Rias Baixas has been able to increase its vineyard area to any significant extent during the 21st century.  The other four DOPs are constrained by their geography and their vineyard areas have remained more or less constant.  Wine production from these DOPs isn’t going to markedly increase anytime soon.  So if you want to taste Palacios’ Godello from Valdeorras or Peza do Rei’s Mencia from Ribeira Sacra, you’ll have to be prepared to pay for these delights.  Hopefully you’ll take some comfort from an appreciation as to why production is so limited and why their production costs are so high.




The Grape Varietals of Galicia’s D.O. Ribeira Sacra

The relatively unknown wine region of D.O. Ribeira Sacra was in the news recently when it emerged that a red Peza do Rei 2011 would be served to President Obama at a Gala dinner.  This producer usually makes red wine with 100% Mencia, but what other grape varietals are available in the Ribeira Sacra vineyard?

Ribeira-Sacra-Production-byUnlike the neighbouring Galician D.O. of Rias Biaxas (whose vineyard is dominated by the white varietal Albariño), the D.O. Ribeira Sacra vineyard is dominated by black vines.  White grapes have made up less than 10% of total grape production for every year this century and for the last eight years their contribution has been under 5%.  The D.O. regulations permit the white varietals Albariño, Godello, Treixadura, Loreira, Torrontes and Dona Branca.  Of these, Godello is the most important and typically contributes >70% of white grape production.  Albarino is the second most important white grape with a contribution of ca. 15%.

Ribeira-Sacra-Black-VarietaThe black varietal vineyard is dominated by Mencia, which has comprised >90% of black grape production every year this century.  Apart from Mencia, the other recommended black grape varietals for D.O. Ribeira Sacra include Brancellao, Caino tinto, Merenzao and Souson.  These varietals make up a tiny part of the vineyard and in 2012 their combined contribution was <1% of black grape production.  More important is Tempranillo (also recommended) but more important still is the permitted varietal Garnacha tintorera, which made up 6% of black grape production.


Winners and Losers in Spain’s Evolving Vineyard

Spain had ca. 1 million hectares of land occupied by vineyards in 2012, the largest of any country.  Yet only a quarter of a century ago, this figure was  50% greater (1.5 million ha).  As the national vineyard continues to evolve, which of the country’s regions are winners (expanding) and which are losers (decreasing)?Spain-Vineyard-Area

In the second half of the 20th century Spanish winegrowers faced the twin threat of decreasing per capita wine consumption at home and increasing competition from New World producers in export markets.  Domestic wine consumption went from ca. 60 litres per capita per annum in 1980 to about half that figure by the end of the century.  Demand for table wines were particularly hard hit as Spanish consumers turned their attention to quality wines.  With vineyard yields and wine stocks increasing, whilst prices were falling, Spain began to reduce the size of its vineyard in 1980.  With Spain’s entry into the EU in 1986, it became subject to the Common Agricultural Policy (CAP) which then subsidised vine-pulls, especially for lower quality vines.  All these factors contributed to not only the overall shrinking of Spain’s national vineyard, but for those vineyard areas outside of Denmonación de Origen Protegida (DOP) regions to be disproportionately affected.Spain-DO-areas-declining

Since 1990 Spain’s total DOP vineyard area has remained roughly constant at ca. 600,000 ha.  Yet within this space there has been much jockeying for position, reflecting the ease, or otherwise, of commercialising the wines from a particular DOP.  The greatest vineyard losses in the 21st century have been in La Mancha DOP (down by ca. 31,000 ha) and Jumilla DOP (down by ca. 18,000 ha).  A number of much smaller DOPs have lost between a third and a half of their vineyard area including Alicante, Méntrida, Montilla-Moriles, Calatyud and Condado de Huelva.

Spain-DO-areas-increasing-2Those DOPs that have been able to significantly increase their size in the 21st century are presumably enjoying a greater than average commercial success.  They include well known DOPs such as Rioja (+ ca. 5,500 ha), Ribera del Duero, Rueda, Rias Baixas and Priorat.  Yet the greatest vineyard gain in the 21st century has been at Extremadura’s less well known Ribera del Guadiana DOP (+ ca. 18,000 ha),   Only established as a DOP in 1999, Ribera del Guadiana’s success appears to based on vinifying Tempranillo in a fruity “New World” style.