Trento

The Trento rules set the sparkling wine in a long local tradition: grape seeds from the Bronze Age pile dwellings at Ledro, the Cembra situla of the fourth century BC praising wine, and the historian Michelangelo Mariani, who in 1670 described almost all of Trentino as wine country. The founding of the agricultural institute of San Michele all'Adige in 1874 was a turning point.

Sparkling wine by the bottle-fermentation method has been made in Trentino since the early 1900s, and the rules say production grew without interruption through the century, in producers and in bottles. It was first protected as a type within the Trentino DOC. On 9 July 1993 the separate Trento DOC was recognised, the first Italian denomination reserved only for sparkling wine made by refermentation in bottle. The consortium markets it as Trentodoc.

The zone covers suitable plots in 74 communes of the province of Trento, in the Adige, Cembra, Lagarina, Sarca, Sugana and Giudicarie valleys. Other denominations overlap the same land; vineyards registered for Trento cover about 800 ha. ISTAT classes the whole area as mountain, with only about 10% flat valley floor, and 70% of Trentino lies above 1000 m. Vineyards are mostly on slopes up to 800 m; the consortium gives 200-800 m.

On the slopes, soils are stony limestone scree on the middle and upper parts of alluvial fans, which drain and aerate well; lower down they are less stony, with colluvium, moraine and river gravel. Porphyry appears in the Cembra valley, basalt at Isera, Mori and Brentonico, and mica-schist in the Valsugana. Winters are fairly cold and snowy, summers hot; near Lake Garda and the lower Sarca the climate is sub-Mediterranean, softened by the lake and the daily Ora breeze. Rain there averages 900-1000 mm, mainly in spring and autumn.

The rules describe sparkling wines with balanced chemistry, especially between acidity and alcohol, and aromas that clearly reflect their grapes. They credit the wide day-night temperature swing of the last weeks of ripening with the finesse of scent that marks them, and note that grapes for Trento are picked earlier than those for still wine, to keep the balance of sugar and acidity a sparkling wine needs. The consortium adds that research by the Fondazione Mach and the Ministry found that certain volatile compounds, formed under these mountain temperature swings, can identify a Trentodoc.

Only Chardonnay, Pinot Bianco, Pinot Noir and Meunier may be used. Grapes are usually vinified by variety and blended into a cuvée. Vines are trained on single or double pergola or on vertical wires (Guyot, spurred cordon), according to the slope and the producer's aim. The only method allowed is second fermentation in bottle, with riddling (remuage) and disgorging. The wine must stay on its lees for at least 15 months, counted from bottling and not before 1 January after the harvest; 24 months to show a vintage and 36 for a Riserva, which must be vintage-dated.