Only sparkling wine made in the region of Champagne in France can be called Champagne. The grapes are harvested and yeast is added to the grape juice to induce fermentation. Sugar and yeast are then added to the wine a second time before bottling, which allows a second fermentation to occur in the bottle. It is this second fermentation which produces the characteristic bubbles, and the remaining yeast gives Champagne its unique bready flavour.