When Sonoma County is on a wine label, good things happen.

That was the message wineries heard Wednesday during the official launch of a campaign to pass a law requiring wines from Sonoma County's 12 sub-appellations like Alexander Valley and Bennett Valley to also print "Sonoma County" on their labels.

Research released at the annual meeting of the Sonoma Vintners trade group showed consumers often have a better impression of a wine's quality if it includes both the American Viticultural Area and "Sonoma County" on the label.

It's called conjunctive labeling, and it has been used in France for years, in Napa since 1987, and Paso Robles since 2008. The idea has been kicking around Sonoma County for more than a decade, but this is the first concerted effort to get Sonoma its own law.

Some wineries, especially ones in well-known or exclusive regions like Russian River Valley or Chalk Hill, feel that putting the name of their AVA on the label is sufficient, and adding Sonoma County would only confuse consumers.

But Honore Comfort, the group's executive director, said new research proves consumers' impressions of the wine is only enhanced when Sonoma is on the label, too.

"The research makes a strong case for the value and benefit of conjunctive labeling for Sonoma County, while dispelling several of the key concerns wineries have had in the past," Comfort said.

A nationwide survey conducted by Christian Miller of Wine Opinions, showed three versions of the same fictional wine label to three different group of wine drinkers. One contained only Sonoma County, the other featured the AVA followed by Sonoma County, and the third listed just the AVA.

In most cases, the addition of Sonoma County to an AVA wine increased consumers' impressions of its quality and price, Miller said.

In addition, interviews with a panel of people in the wine trade strongly agreed -- by 81 percent -- that adding Sonoma to the label would make it clearer for consumers.

"They think this will help them sell more of your wine," Miller said.

Winery owners in attendance seemed uniformly in agreement with the initiative. Chris Lynch, owner of the Dry Creek Valley winery Mutt Lynch west of Healdsburg, said his winery only puts Dry Creek on the label, and it's a problem for him as he travels the nation trying to sell it.

"I've met a lot of trade and huge number of consumers who have no idea where Dry Creek is," said Lynch, who is a member of the Sonoma Vintners marketing committee that worked on the proposal.

One potential snag could be opposition from wineries in the three AVAs that already have Sonoma in their names -- Sonoma Valley, Sonoma Mountain and Sonoma Coast. Currently, the plan calls for them, too, to also have Sonoma County on their labels, in slightly smaller print.

While this may be duplicative and confusing to some consumers initially, over time it will become clear, Lynch said.

"At some point the repetition clarifies it," he said.

If approved by the state Legislature, the law would be phased in after three years to give wineries time to adjust.

The current timeline calls for the vintners to get responses from members over the next three months, make a final recommendation by April, draft legislation over the summer, and get it passed in the fall.