Geography, climate change, and a few dinosaurs
The table below shows the approximate sizes and differences in soil type of the six terroirs. The soils in each–and indeed, within each terroir–can have dramatic differences. In one place you might find a lot of sand, and only 700 meters away the soil might be very chalky.
|Growth Area / Cru||Size||Characteristics|
|Grande Champagne||34 700 hectares / 13 250 ha covered with vineyards||Rather hilly, a chalk soil|
|Petite Champagne||65 600 ha / 15 250 ha covered with vineyards||Chalky but soil more compact than the Grande Champagne|
|Borderies||12 500 ha / 4 000 ha covered with vineyards||On a plateau, with a soil of clay and flint stones|
|Fins Bois||350 000 ha / 31 200 ha covered with vineyards||Mixed soil: red, clay, and limestone|
|Bons Bois||370 000 ha / 9 300 ha covered with vineyards||Very mixed soils, clay, limestone, sands|
|Bois Ordinaires||260 000 ha / 1066 ha covered with vineyards||Mainly sand soils, including islands Ile de Ré and Ile d’Oléron|
The soil in the Cognac region is pretty extraordinary. It’s part of a region known as the Aquitaine basin, and has been formed thanks to global climate change over the millennia. The seas moved inland and out again, laying down layers of marine sedimentary deposits from as early as the Jurassic period. And yes, this makes for soils that really do contain micro remains of dinosaurs. Throw erosion and tectonic forces into the mix, fast forward 200 million years to today, and you end up with a landscape that is totally dominated by chalk.
In the mid 1800s a detailed evaluation of the Cognac landscape was undertaken by local geologist, Henri Coquand. This took him over a decade to complete, and was the first in-depth geological survey ever carried out in the area. In addition Coquand was accompanied by an oenologist, an expert in the science and study of wine making. Not only did their results determine the boundaries of the individual terroirs, but also how best the wine from each region would be distilled and aged, as well as the quality that each produced.
In addition, he also identified five specific types of soil that were particularly suited for the production of the best quality Cognac. We’ll talk more about these soils in the individual growth region descriptions below. As you’re about to find out, the production of Cognac has as much to do with the chalk content of the soil as anything else. And if you thought chalk was simply chalk, then think again. Because the type of chalk contained within the soil really does determine the taste of the Cognac you drink today. Chalk makes soil crumbly and friable. It’s this physical property that’s so important to the grapes that grow here.
So what’s the big deal about chalk?
There are two main reasons that the chalk content and type is so important. The first is that it lends itself to good drainage, whilst still keeping a good percentage of moisture. Being as this region of France has a temperate climate, with some hot, dry spells during spring and summer, this is very important to allow the deep roots of the vines to keep well hydrated. These roots can grow to a depth of 25 meters, so the ability for a constant supply of water is paramount for the successful growth of the fruit.
Secondly, grapes grown in chalky soils are higher in acidity. And this acid content is vital to produce good Cognac. While you certainly wouldn’t look for such a quality in a wine, for Cognac, it’s essential.