Pedology is the study of soil as opposed to geology which is the study of subsoils. Soil is made up of several strata, varying in texture, structure and colour. This soil evolves constantly towards a balance between soil, vegetation and climate: it is a superficial layer of firm earth, more or less soft and friable, resulting from the decomposition and the transformation of the underlying mother rock under the effect of physico-chemico-biological agents.
The vineyards of Champagne are situated at the northern limit of the zone for the cultivation of vines (extreme conditions are always favourable to greatness!!!). They occupy the Île de France Cuesta which marks the boundary between the Tertiary plateaux of the centre of the Paris basin and the plain of chalky Champagne. The relief of this cuesta forms a vast east-facing versant, whose variations in level range from 60 to 120 metres. The altitude of Larmandier-Bernier’s vineyards varies from 100 to 220 metres, with most of them situated between 110 and 150 metres both in Vertus and Cramant.
The geological composition
of Champagne soil is the result of:
– the presence, originally, of the sea in the region of Champagne,
– the retreat of the sea some 70 million years ago,
– an earthquake 20 million years ago, the effect of which was to raise up the soil and to break up the chalk while at the same time impregnating it with marine elements and minerals,
– a new earthquake of greater intensity 10 million years ago, which brought about the creation of a very undulating terrain.
Apart from the relief, the relationship between sub-soil and soil, the variations in exposition to the sun, the wind currents, … are all factors in the diversification of terroirs. Moreover, in order to obtain quality fruit, the choice of the grape variety must be adapted to the soil. Chardonnay, for example, does not appreciate clay soils, but is very widespread in pure chalk vineyard areas like those in Cramant, Avize, Chouilly…
It is possible to distinguish four areas of grape production, which comprise the various terroirs of Champagne:
The Montagne de Reims – it faces south, east and sometimes even north. The slopes are located on soils in which the chalk lies deep. Pinot Noir is the dominant grape variety.
The Marne Valley – directly south, for one side of the valley, directly north for the other side. The slopes are located on predominantly clay-limestone soils with a tendency towards marl. The principal grape variety is Pinot Meunier.
The Côte des Blancs – the vineyards of the Côte face east and south-east. The outcropping Campanian chalk can be found everywhere, and represents a real reserve of water and heat for the subsoils. Here, a single grape variety reigns supreme: Chardonnay.
The Aube vineyards, Bar-sur-Aube and Bar-sur-Seine – the subsoils, which have a marly tendency, lie on compact Kimmeridgian limestone (much older: 155 million years …) and are mainly planted with Pinot Noir. An altitude which is one hundred metres higher than for the Marne vineyards.
We can look upon chalk as the keystone of our terroirs. Indeed, among these four areas of grape production, only the Montagne de Reims and the Côte des Blancs lie on Campanian chalk.
This chalk of the Late Cretaceous period, dating from 65 million years ago, played an important part in the planting of the vine, and has done for a very long time, since a geologist discovered impressions of vines in the limestone of Sézanne, dating back to the Thanetian era about 55 million years ago. The thickness of this vein of chalk may reach between 200 and 500 metres.
In Champagne, there two types of chalk, belemnite and micraster. Belemnite will be found beneath the best vineyards (the premiers and grands crus) and micaster on the gentler slopes in the south of Champagne.
The chalk containing belemnites is capable of storing up and giving back solar heat and ensuring perfect drainage of water. It enables, moreover, the storage of excess humidity in rainy periods, thus reducing the effects of drought during the summer.
So Cramant and Vertus are situated on the same vein of chalk with belemnites, and yet when you taste these cuvées, “Terre de Vertus” and “Vieille Vigne du Levant”, big differences can be noticed. Perhaps we should avoid trying to characterise and just appreciate their characters.
The pores of chalk are very fine, but very numerous. When they are saturated a cubic metre of chalk can contain as much as 400 litres of water: this is the water table or the phreatic reserve (saturated zone). In the upper part of the chalk bed (between 10 and 20 metres on average below the ground), a proportion of the pores are filled with air (non-saturated zone). Water comes up to the surface from the water table by capillarity. Rainwater slowly penetrates the chalk at a speed of about 50 centimetres per year through the non-saturated zone, which enables the table to be replenished. For the water to move more quickly, it needs to be drained through cracks (diaclases). Given its thickness, chalk constitutes one of the principal water reservoirs of the Paris basin and thus of Champagne.