Terroir & appellation
The subsoil in Champagne is predominantly limestone. So too are the outcrops of sedimentary rock (75% limestone), composed of chalk, marl and limestone proper. This type of subsoil provides good drainage and also imparts that particular mineral flavour found in certain Champagne wines.
The chalk in Champagne consists of granules of calcite formed from the fragile shells of marine micro-organisms (mainly coccolites). Being highly porous, it acts as a reservoir (storing 300-400 litres of water per m3, or 79-105 US gallons) that provides the vines with a steady supply of water even in the driest summers.
Chalk draws in water through capillary action. The effort required to tap into this water supply puts the vines under just enough water stress in the growing season to achieve that delicate balance of ripeness, acidity and berry aroma potential.