With an ABV now of 15% or sometimes even 16%, some appellations seem to have a predisposition for higher alcohol levels. What conclusions should we draw from this?
A geographical explanation
The further south you travel, the greater the sunshine, and the more photosynthesis produces sugar in the grapes. During fermentation, at a rate of about 17 g per degree of alcohol, the sugar turns into ethanol. Also, the plains of the southern Rhone are too far from the Mediterranean to fully benefit from its cool air. Lastly, some villages act as a focal point for the sun’s reflection, such as Châteauneuf du Pape (with its famous pebbles) or Gigondas (with the Dentelles de Montmirail).
But also human input
Unlike the northern Rhone, where red wines are single varietal Syrahs, those from the south are blends, with a predominant proportion of Grenache noir (50% minimum in Côtes-du-Rhône, 80% in Vacqueyras, 90% in Gigondas...). The variety, with its fruit-laden aromas, naturally produces high sugar content.
Another explanation comes from changing tastes. To obtain finer tannins, lower acidity and fruitier wines, the grapes tend to be harvested after a longer hang-time for greater maturity in the skins (even if climate change is leading to earlier harvest dates), and therefore tend to be sweeter.
And then there is climate change itself which, aside from extremes such as the summer heat wave of 2003, generally tends to deplete water and concentrate CO2 in the air. This results in even sweeter grapes due to concentration and greater photosynthesis.
A worthwhile style
The long-standing strength of these wines is not a fault, provided they retain balance. Wine must not go from tasting "warm" to feeling "hot". Winegrowers are fully aware of this and have adapted accordingly.
In the field, some rootstock slow down soaring sugar levels. Canopy management can have an impact on photosynthesis. Grass cover (or not) can add more, or less, water. Woodland surrounding a vineyard helps rein in cool air... In the cellar, selecting yeast strains with a low alcohol transformation rate can also be useful. As an aside, most yeast dies off once the wine reaches around 16%.
Finally, harmony must prevail on the palate. Although by law, labelling must state alcohol content (with a margin of error of 0.5% across Europe), winegrowers minimise ABV as much as possible, because it causes concern amongst consumers. How ironic that in our parents' time, high alcohol content was viewed as a guarantee of quality, and most wine appellations still require a minimum level of alcohol.
Serve these wines chilled, at around 15-16°C, and don't forget to drink water. When they also offer up acidity and minerality, these historic growths are delicious with food. Alcohol then becomes a backbone for taste and texture, and the promise of lengthy ageability.
Written by Alain Echalier