Mediterranean climate and viticulture
By Maurizio Gily
A “cool climate” is the best one to get top quality wines from vineyards: this is what most people believe,
especially in English-speaking countries. From this viewpoint, the wines produced in Southern Italy, which is
considered a warm climate land, may certainly aim at being included among the good wines, yet without
reaching the world’s wine excellence, except for rare exceptions.
In this short paper I will try to explain why, in my humble opinion, based on my experience and some
evidence and recent scientific findings, things aren’t what they seem.
The crucial matters are three: the first one refers to the relationship between indigenous varieties and the
environment, the second one is related to the environment itself and some clichés about climate of
Southern Italy, the third one covers the viticultural "mitigation" of excess heat through the canopy
management.
The theory of "cool climate" has solid foundation, based on both science and experience. My only remark is
its generalization. Many wines produced in Southern Italy (but also in the South of France and Spain),
particularly those made from indigenous grapes, don’t respect this “rule”.
A premise about wine making: the use of cooling systems in the cellar has been the key to their quality
revolution: without them, in large masses, producing quality wines in a warm place would have been
almost impossible. This practice dates back to few decades ago, thus quality wines of South Italy rely on a
quite brief history and this still affects negatively their image. It's time to dispel these prejudices which still
exist.
Vine and environment
With their work and writings, remarkable scientists like Emile Peynaud in France and David Jackson in New
Zealand have explained how quality viticulture is mainly a "borderline" one since vines are sometimes even
hardly grown. However Peynaud has also recognized that these are strongly influenced by the vintage, thus
benefiting from the opportunity to produce a “great wine” just for few vintages, whereas warmer climates
offer a more consistent quality, although (in Peynaud’s opinion) the level is rather lower. The fact that both
Peynaud and Jackson were grown in cool-temperate climate areas (Bordeaux for Peynaud and Christchurch
for Jackson) may raise some doubts of impartiality. But this is not the point.
The first objection focuses on the relationship between grape variety and environment. In a 1993 work
published on the American Journal of Enology and Viticulture, and widely cited in the literature, Jackson
and Lombard compare the climates of some world's wine-growing areas and the period of harvest of three
common worldwide spread varieties. They observe that the best wines are obtained where the grapes
ripen in the "alpha" area with average temperatures below 15 degrees (Celsius) during the ripening. The
maturation at too hot temperatures- this is what Jackson and Lombard explain - causes a "misalignment"
between the sugar upload (too early), the physiological ripening (sugar / acid ratio, with excessive fall of the
latter), phenolic ripening (when sugars are already high, tannins aren’t ripe) the aromatic ripening (with
loss of aromatic precursors due to oxidation and respiration) and the color ripening (the same problem of
aromatic precursors).
©Maurizio Gily, 2015
In Perth, Australia, all the three varieties taken into consideration mature too early (beta zone) to the
detriment of quality, while in Christchurch , New Zealand, all the three varieties ripen in alpha zone.
Jackson, who was a teacher in Christchurch, omits to say that the Cabernet Sauvignon in Christchurch
hardly ripens in a cooler year! But the real question is: which are the varieties examined by Jackson and
Lombard? Two varieties from cool climates, Pinot Noir and Riesling, as well as a grape from a temperate
oceanic climate, the Cabernet Sauvignon.
By Jackson and Lombard, 1993
B = budburst
F = flowering
V = veraison
H = harvest
©Maurizio Gily, 2015
This choice is justified by the widespread use of these grapes in the New World: but can we apply these
conclusions to those regions where completely different varieties have been mostly grown- due to the way
they adapt to the local environment-? Definitely not.
First of all, southern varieties are generally later ripening than Cabernet sauvignon, and much later than
Pinot noir. They often approach the alpha area, especially at altitudes exceeding 400 meters (Irpinia,
Vulture, Alta Murgia, Etna); secondly their response to high temperatures is different from that of the
Central European grape varieties. They often have high fixed acidity, which makes these grapes unsuitable
to cooler climates, where they would give too aggressive wines. Then there is a physiological mechanism to
take into consideration. At extremely Summer high temperatures some varieties, more than others, stop
the photosynthesis through the mechanism of stomatal closure, thus delaying the ripening cycle. The
stomata are the openings of the leaf through which gaseous exchanges take place, as well as the loss of
water vapor and oxygen and the input of carbon dioxide. For this reason the closure of the stomata
involves the blocking of photosynthesis, which takes over when the temperature drops. In cooler climate
vineyards this closure takes place to a limited extent (isohydric behavior), so the basal leaves dehydrate
because of the excessive perspiration and may fall, exposing the bunches to the direct sunlight, which can
burn them, and over-ripening phenomena may also occur.
The climate: warm, but ...
Wladimir Köppen is the most famous among modern climatologists. He created a universally accepted
classification of the world climates. In this classification, the Mediterranean climate is a subset (s) of the
larger group of temperate climates (defined as those where the coldest month has an average temperature
between -3 and +18 ° C) and its distinctive feature is a dry summer in the respective hemisphere (high sun
position).
The mitigating effect of the sea limits the continentality, that’s to say the temperature difference between
summer and winter, and prevents the temperature from rising too much in summer (except for the
occasional presence of sirocco wind from Saharan Africa) while winters are mild.
Beyond the general blandness, another feature belonging to the Mediterranean climate , as we have seen,
consists in a dry season, with little or no rainfall, along with the warmer months, and a wetter winter
season (the exact opposite of what occurs in tropical climates). In any case the annual rainfall is low (less
than 600 mm) while the level of solar radiation in the growing season is very high, as the sky is almost
always clear: with obvious consequences, among other things, on the health of the fruit and low impact of
fungicide defense.
Regions classified by Köppen as Mediterranean are shown in the following map.
©Maurizio Gily, 2015
Apart from southern Italy, south French regions and the Iberian peninsula are involved, as well as Greece,
the north coast of the Maghreb countries and much of the Mediterranean coast (hence the name), but also
California, sub- coastal South Africa, much of Chile, South Australia (Adelaide) and the West (Margaret
River). These are all traditionally wine-growing regions. This is a rough classification since there are climatic
differences between these areas, especially in terms of temperatures, depending on the latitude and the
relieving effect of the sea, which is stronger in islands and peninsular offshoots as Puglia and Calabria.
South Italy and France represent, in this sense, the Northern Mediterranean.
Mitigating factors heat: altitude and wind
Most wine-growing areas in Southern Italy are located at altitude, thus avoiding the risk of excessive heat.
Among the best known wines produced in these areas there are all the wines belonging to the Etna area, as
well as Taurasi, Aglianico del Vulture, most of the Fiano, Greco and Falanghina from Campania, different
wines of high ground of the Sicilian mountains and the Apulian Murgia.
As far the coastal areas we have to take into consideration the relieving effect of the wind, as well as of the
sea. As shown in the map below, the windiest areas of Italy are the Southern parts of Sicily and Sardinia,
and Salento too. The effect of the wind consists in standardizing the temperature of the fruit to that of the
air. At a temperature of 35° degrees Celsius (95° F), when it’s not windy, a cluster of black grape hit by the
sun reaches and exceeds the temperature of 50 degrees C. (122 F). If it’s windy its temperature reaches the
same level of that of the air (35°). We've all experienced this phenomenon parking the car in the full
sunlight of a summer windy day if compared to what happens when the air is still.
©Maurizio Gily, 2015
Canopy management to cope with climate: the bushvine
The tradition of southern Italy, as well as of other
Mediterranean countries, at least in the warmer areas,
provides only for a partial exposure of the fruit to the
direct sunlight. The traditional method to reach this goal
is the bushvine. Where the soil is more fertile and fresh,
as it is in some areas of Campania, Lazio and Abruzzo
they use a overhead, horizontal canopy (pergola). The
bushvine has been partly abandoned in recent decades
as it hasn’t proved to be suitable for mechanization and
thus it has been turned into partial VSP (vertical shoot
©Maurizio Gily, 2015
positioning) trellis systems,yet keeping a form of umbrella in the highest part of the canopy, obtained by
making the top of the shoots fall downward.
The aromatic precursors
A widespread notion is related to the negative effect of high temperatures on aroma precursors and the
positive effect of the excursion temperature variation. To stress how inaccurate this dogma is, it would be
enough to point out that one of the most prestigious wine-growing areas of the world, the Médoc, Atlantic
peninsula, usually enjoys modest day/night temperature variations.
Recent studies have confirmed how negative excessive heat peaks are on the bunches. However some
aromatic precursors, in particular norisoprenoids (aromas of tropical fruit and candied) develop better
during mild nights (not too cold), while other precursors (terpyneols, benzenoids) show the opposite
behavior. Since it’s a rather complex mechanism which is not fully understood, we’d better be very careful
before embracing easy simplifications.
Take the Chardonnay as an example, the most adaptable to the climate among the cultivated varieties.
Chablis and Chardonnay from Sicily can be both rich in aroma, but very different as far their flavor
spectrum.
I would conclude my paper mentioning a North Italian man’s opinion (I live in Piedmont) given by his long
lasting experience in Southern viticulture.
In ancient times the wines belonging to the Mediterranean area dictated the paradigm of quality which was
then acquired by the northernmost wine in the twentieth century. In the twenty-first century it’s time to
appreciate the character of quality wines produced in different territories and from different grapes (which
have been grown for centuries in these lands) using flexibility. The Mediterranean wines aren’t better, and
aren’t worse: they are different. In essence, this has been already understood by the market.
Maurizio Gily
viticulturist
www.gily.it
©Maurizio Gily, 2015