Northern Italian Prosecco under European law. Hence, since 1 January 2010, Prosecco is, according to an order of the Italian Minister of Agriculture of 17 July 2009, no longer the name of a grape variety (now to be called Glera), but exclusively a geographical indication. This was confirmed by EG-Regulation Nr. 1166/2009 of 30 November 2009. The Colli Asolani Prosecco Superiore DOCG later changed its name to Asolo Prosecco Superiore DOCG in 2014. Production Unlike Champagne and Franciacorta DOCG, Prosecco is usually produced using the alternative Charmat–Martinotti method, in which the secondary fermentation takes place in large stainless steel tanks rather than in each individual bottle, making the wine less expensive to produce, and the minimum production time is 30 days. Higher quality Prosecco using this method will ferment the wine over a longer period, up to around 9 months (Charmat Lungo). Nevertheless, the production rules for both the DOCG's also allow the use of the traditional method of secondary fermentation in the bottle, known in Italy as Metodo Classico. DOC and DOCG rules allow up to 15% of Prosecco wine to be a blend of Verdiso, Bianchetta Trevigiana, Perera, Chardonnay, Pinot Bianco, Pinot Grigio, or Pinot Noir (vinified white). Approximately 150 million bottles of Prosecco were produced in 2008. Huge subsequent growth meant this figure approached 600 million bottles in 2018. Since the 2000s, Glera grapes are cultivated and wine produced in other countries including Brazil, Romania, Argentina, and Australia. In the region of Conegliano and Valdobbiadene DOCG, there are more than 150 producers, and together they form the Consortium for the Protection of Prosecco from Conegliano and Valdobbiadene (Consorzio per la Tutela del Prosecco di Conegliano e Valdobbiadene). DOCG also has its own consorzio, with 94 producers. Prosecco DOC Most Prosecco, whether DOC or DOCG, is made as Spumante sparkling wine or Frizzante (semi-sparkling). Prosecco DOC Spumante is the most famous and popular variety, with longer-lasting bubbles. Prosecco DOC Frizzante has less lingering bubbles. A small proportion is made as Tranquillo (still wine), with no bubbles. Tranquillo amounts to only about five per cent of production, and this wine is rarely exported. Depending on their sweetness, in accordance with the EU Sweetness of wine Regulations for Terms used to indicate sweetness of sparkling wine, Proseccos are labelled "Brut" (up to 12 grams per litre of residual sugar), "Extra Dry" (12–17 g/L) or "Dry" (17–32 g/L). Extra-Dry has been