Austrian term for a partially fermented grape must that must come exclusively from grapes harvested and processed in Austria. The name is derived from the "stormy" sound of the beverage, which is rich in carbonic acid. It is an EU-wide origin-protected traditional term, so it must be designated with a country wine origin (Bergland, Steirerland or Weinland). The existing alcohol content must be at least 1.0% vol. Due to the potential continued fermentation, this can increase to 10% alcohol by volume, which is mostly prevented by cooling. The total alcohol content must not exceed 13.5% vol (white) or 14.5% vol (red).