According to Wikipedia Asti or Asti Spumante is a *DOCG white sparkling wine produced in an area to the south of the town of Asti in Piedmont, Italy. Made from the Moscato Bianco grape, it is sweet and low in alcohol, and often drunk with dessert. It retains its sweetness through a complex filtration process.
DOCG or Denominazione di origine controllata is an Italian quality assurance label for food products and especially wines. modelled after the French AOC and was instituted in 1963 and overhauled in 1992 for compliance with the equivalent EU law on Protected Designation of Origin, which came into effect that year.Actually, there are three levels of labels:
DOC — Denominazione di Origine Controllata
DOCG — Denominazione di Origine Controllata e Garantita
DO — Denominazione di Origine
All three require that a food product be produced within the specified region using defined methods and that it satisfies a defined quality standard.
DOCG regions are subterritories of DOC regions that produce outstanding products that may be subject to more stringent production and quality standards than the same products from the surrounding DOC region