First of all, Champagne means three grape varieties: Chardonnay, Pinot Noir and Pinot Meunier. Chardonnay is a white grape; the two Pinots are both black. Each brings something special to a blend. Chardonnay suggests flowers, vanilla, honey; Pinot Noir is earthier, rootier, more structured; Pinot Meunier adds fresh, appley notes.
Secondly, Champagne is the name of a place in northern France. It’s a range of low chalk hills which rise gently up from a dreary agricultural plain east of Paris. The hills drain the chalk and lift the vines towards the sun, allowing them to achieve the barest minimum of ripeness. Turn those grapes into wine, and their nervy, high-acid profile is perfect base material with which to make great sparkling wine. True Champagne, therefore, comes only from Champagne.
Thirdly, Champagne is made by a unique method, now imitated wherever winegrowers want to make great sparkling wine. The Champagne method begins with still wine made from Chardonnay, Pinot Noir and Pinot Meunier grown within the Champagne area. That wine is then bottled with a little extra sugar and yeast, and carefully laid on its side in the cool, deep cellars which honeycomb the region.