US tax authorities have approved changes in vintage regulations for wine.

The Alcohol and Tobacco Tax & Trade Bureau has cut the minimum content requirement from a certain vintage from 95% to 85% on wine from state and county designations.

The change was opposed by California's Winegrape Growers, who argued that wineries would carry over cheap surpluses from previous years for future blending. The organisation argued that consumers want vintage-blending information included on labels.

Supporters said the new regulations would improve the taste of young wines using a blend of older wine, and provide the US industry with a boost to compete with Australia and other competitors that have lower vintage regulations.

Napa Valley Vintners suggested that wine created from blended vintages should not bear a vintage date.