The most sweeping revision of wine regulations since the 1930s was announced here yesterday. As a result, consumers can expect more cabernet in a wine labeled "cabernet sauvignon" and a clearer idea of where the wine they buy actually comes from.

It took three years of petitions, written comments and public hearings for the Treasury Department's Bureau of Alcohol, Tobacco and Firearms to formulate what one official termed "the first attempt to modernize the labeling regs in terms of increasing consumer interest and marketing activity in the U.S. and abroad." Sales of domestic (now "American" according to the new regulations) wines have nearly doubled in the decade between 1966 and 1976.

A number of the reforms were proposed by the industry itself. Several consumer proposals were adopted as well, though the most ambitious, a call for a system of vineyard quality classification, was dropped.

Italy, France and Germany, the leading European producers, all have systems that officially recognize the graphic areas, be it a region such as Chianti Classico in Italy, a town (bernkastel in Germany) or a specific vineyard (Romance-Conti in France). An early proposal by the bureau to create a "seal" for wines produced in designated areas drew heavy fire. It would, critics said, lead consumers to believe government-endorsed wines were better than those without the seal.

Among the innovations that survived are:

A provision that varietal wines (such as cabernet sauvignon) must contain at least 75 percent of the variety listed on the label. At the original minimum, 51 percent, the varietal character of wine often was indistinguishable. On the other hand, a strict 100 percent requirement was felt to limit blending to improve quality, as is done in Bordeaux and other centers of wine production. An exception was made for Labrusca and Muscadine varieties (wines from the native Concord grape and others). They are considered too strong to be palatable unless cut below 75 percent.

At least 85 percent of the grapes in a wine that claims a specific geographical area (Napa Valley, for example) must be grown in that area. The requirement is only 75 percent, however, if the wine claims county or state origin.

The term "estate bottled" may be used if the bottling winery "grew all of the grapes used to make the wine on land which it owned or controlled within a viticultural area."

A continuation of the requirement that 95 percent of the wine given a vintage (such as 1976) be harvested in that year.

The addition of the word "Brand" to any artificial name that misleads the consumer as to a wine's origin.If "Sonoma Creek" for example were really a factory in Oakland, it would have to become Sonoma Creek Brand.

A provision to allow multi-county and multi-state wines to be produced under strict conditions.

The bureau announced it will soon begin "holding hearings to determine the precise boundaries of viticultural areas" and left open the door for new regulatory initiatives in several years.