(Bloomberg) - Italy just produced the biggest grape crop ever for Prosecco, a sparkling wine that set sales records in recent years. Prices aren’t likely to drop anytime soon, because vintners are stockpiling the surplus.

Near-ideal growing conditions this summer led to bumper grape harvests across Italy, which is poised to overtake France as the world’s biggest wine producer. With Prosecco output surging as much as 56 percent this year to 3.5 million hectoliters (467 million bottles), the organization that manages the appellation expects 300,000 to 500,000 hectoliters will be put in storage tanks for a year or longer.

Vintners say they’ll need the surplus later, because demand is skyrocketing. The Prosecco industry forecasts global sales will jump 20 percent this year to 1.68 billion euros ($1.84 billion). At about $12 a bottle, the wine has become increasingly popular among younger drinkers in the U.K. and U.S. as an alternative to French Champagne that costs $52 on average. To keep up, winemakers expanded planting in the northeast regions of Veneto and Friuli Venezia Giulia designated for Prosecco grapes.

Never have there been so many grapes harvested for production of our wines,” Stefano Zanette, president of the Treviso, Italy-based Prosecco DOC Consortium, said in an e-mail.
While production has more than tripled since 2009 -- mostly from increased planting that now covers 20,000 hectares (50,000 acres) -- the new vines take about three years to reach full harvest. Regional governments restrict how much of the annual yield can be used to make Prosecco, usually 18 metric tons per hectare (2.47 acres), said Luca Giavi, the Consortium director. That helps control supply and preserve quality, because too many grapes on the vine can affect the taste of the fruit.

Grape Overflow
This year, the Consortium altered those limits and allowed a reserve for the first time as vineyards overflowed with quality grapes, including the glera variety, which by law must make up at least 85 percent of the wine. Steady summer rains and temperatures just above average had allowed the berries to ripen with very little disease. The yield limit was raised to a record 21.6 tons per hectare, with anything over 18 tons stockpiled, Zanette said. A recent survey of growers showed they were delivering about 2.5 tons per hectare to reserves.