Prosecco comes from the Italian states of Veneto and Friuli-Venezia-Giulia.
Prosecco used to be the name of the grape, and could be made anywhere in Italy. Once it achieved international fame, producers fought for exclusivity of the word. They expanded the region to include the town of Prosecco, and created a DOC. The grape then became known as Glera. Now no one outside of the area can use the word.
The region has a warm continental climate. Glera (neutral, lemon, floral) is often blended with Glera Lunga (spicy, concentrated, 15% of blend). Other grapes allowed are Verdiso, Perera, Bianchetta, Trevigiana, Pinot Noir and Chardonnay. Prosecco differs from Champagne in production as produced using the tank method (Metodo Italiano, Charmat process). After the first fermentation, the wine undergoes secondary fermentation in pressurized stainless steel tanks. It is then bottled under pressure. Glera is best suited for this, as its fruitiness is preserved. About 90% of Prosecco is Spumante, and 10% Frizzante (slightly sparkling).
Prosecco DOC can be made anywhere in a vast area including Veneto and Friuli-Venezia-Giulia. Growing in popularity, Prosecco is an easy to drink neutral wine. Most is extra dry (12-17g/l), and a small amount is Dry (17-32g/l). A larger percentage is becoming Brut (0-12g/l). This is the fastest growing category.
Prosecco di Treviso is a smaller but higher quality area.
Conegliano Valdobbiadene Prosecco Superiore DOCG is the best and most classic area. Some want to separate this region from using the Prosecco word, but the name is hard to say, and many just say Prosecco Superiore. Wines are fruitier and more tropical. There are 43 Rive, or Crus. The small Asolo area was just awarded DOCG status
Superiore di Cartizze is a grand Cru vineyard, the best. Prosecco is usually not on the label. There are 106 acres of old Glera vines on this hill, making the best of the best. These are light and creamy wines with medium sweetness.