The soil is mostly of the same white, chalky clay that forms the white cliffs of Dover on the English Channel. Champagnes go through an initial fermentation in tanks that form a very acidic still wine. Next the wine is put through a second fermentation in an individual bottle. The CO2 that is formed during this second fermentation is trapped in the bottle and over a period of time is forced into solution with the wine. The longer that Champagne ages in the cellars, the tinier the bubbles.
Champagne comes in a variety of sweetness levels.
By far the most popular is a style know as 'Brut' which is fermented to dryness. In North America, a slightly sweeter type know as Extra Dry has a substantial market share. In the length of its valley are produced some of the finest white wines made anywhere in France. Near the coast, Chenin Blanc is the preferred grape and Vouvray is the wine produced. Further up the river, Sauvignon Blanc is the grape of choice with Sancerre and Pouilly Fume as the wines that are produced.