What is Prosecco? Or the Conegliano Valdobbiadene Prosecco DOCG?

What is Prosecco? Is it a region, a wine, or a grape variety? Well, before 2009 this term described all three. Pretty confusing, right? As a result, in 2009 several changes were made. First, the Prosecco DOC was created which covers a vast area spanning two regions, nine provinces, and 556 townships. It is geographically located north of Venice in parts of Veneto and Friuli. At the same time the historical birthplace of Prosecco, Conegliano Valdobbiadene, was granted DOCG status. This is a region of steep hillsides located between the villages of Conegliano and Valdobbiadene. And finally, the name of the primary grape variety used in making Prosecco wine was changed from Prosecco to Glera - a historical synonym.
I learned these facts as well as dozens more while attending a seminar presented by US Ambassador of Prosecco DOCG Alan Tardi on the Conegliano Valdobbiadene Prosecco DOCG. I borrow liberally here from Mr. Tardi's presentation.
The word Prosecco is most likely Slovenian in origin "derived from prosek, a dialectic term for 'path cut through the woods'". In Croatia a sweet passito wine called Prošek has been made for thousands of years - although the EU has now banned that usage. I guess it's name is too similar to the subject of this post which was named after the village Prosecco located near Trieste. The first known mention of Prosecco occurred in 1593 when an English traveler named Fynes Moryson wrote "[In] Histria (Trieste) proper grows the wine Pucinum, now called Prosecho, much celebrated by Pliny". Pucinum refers an ancient wine drunk by the Romans.
The modern history of Prosecco began in 1876 when enologist Giovanni Battista Cerletti founded the Scuola Enologico in Conegliano. However the wine's popularity accelerated with improved production techniques for secondary fermentation starting with Federico Martinotti patenting a method using large pressurized temperature-controlled receptacles. And Eugène Charmat's adoption of the autoclave in secondary fermentation soon followed. Post WWII this autoclave became "widely adopted throughout the area of Conegliano Valdobbiadene and the modern sparkling wine industry was born". Over time this historical region lost focus as more producers outside the region began producing Prosecco sparkling wine. Thus the 2009 reforms.
Today the Conegliano Valdobbiadene Prosecco DOCG comprises 15 hillside towns with thousands of small growers supplying 183 wineries. The Dolomite Mountains protect the area on the north while the Piave River valley and a flat plain to the Adriatic Sea bring sea breezes and a semi-marine climate.  The vines are planted on south facing sloops and receive abundant rain which drains quickly through the loose soil or dry from the maritime breezes.
There are three styles of wine made in this DOCG: Spumante (95% of production), Frizzante, and Tranquillo (Still). And there are three categories of residual sugar: Dry (17-32 grams of residual sugar), Extra-Dry (12-17 grams), and Brut (0-12 grams). A fourth category, Extra Brut, was just adopted and will incorporate wines from 0-6 grams.
Other requirements include that the grapes in a Prosecco wine must be at least 85% Glera with the remaining 15% from other authorized grape varieties. Secondary fermentation can be achieved via the autoclave method or in the bottle ("Rifermentato in Bottiglia"). And finally labeling. Superiore refers to only Spumante wines made within the ConVal DOCG. Millesimato indicates a wine made from a single vintage (85% minimum). And Rive indicates a Prosecco Superiore made entirely of grapes from one of the designated Rive (villages).
Here are the wines we tasted during the seminar. Check out those price points and all are highly recommended:
Val d’Oca: Valdobbiadene Prosecco Superiore DOCG Extra Dry ($14)
San Feletto: Conegliano Valdobbiadene Prosecco Superiore DOCG Extra Dry ($17)
Bellenda: Conegliano Valdobbiadene Prosecco Superiore DOCG Extra Dry Miraval ($16)
Vettori: Valdobbiadene Prosecco Superiore DOCG Brut ($16)
Frassinelli: Conegliano Valdobbiadene Prosecco Superiore DOCG Brut ($12 )
De Faveri: Valdobbiadene Prosecco Superiore DOCG G e G Millesimato 2015 ($31)
La Tordera: Valdobbiadene Prosecco Superiore DOCG Brut  "Otreval" Zero zuccheri Rive di Guia 2015 ($20)
Le Colture: Valdobbiadene DOCG Superiore di Cartizze Dry ($35)
Le Vigne di Alice: Conegliano Valdobbiadene Prosecco DOCG Frizzante rifermentato in bottiglia "Col Fondo" ($20)