MCC (Method Cap Classique)

Like Champagne, MCC, is all about a second fermentation in the wine bottle. Once the first fermentation is complete, the Cellar Master adds a bit of fresh yeast and a few grams of sugar to every single bottle before bottling with a 'crown cork' (essentially, a bottle cap which can be easily removed). 

MCC (and Champagne) is different to Sparkling Wine where carbon dioxide is added later in the process. MCC also has smaller bubbles, similar to Champagne.