How do two of the world's most respected winemakers, who happen to be husband and wife, craft a wine together?

With crystal-clear roles. Razor sharp lines drawn in the vineyard and cellar. You do this. I do this. Then, we'll convene over a barrel and blend.

Fortunately, famed Napa winemakers Heidi Peterson Barrett and Bo Barrett both believe in balanced, sun-grown cabernet sauvignon that reflects the unique piece of Calistoga from which the grapes are grown. They just play different roles in getting there. Bo's place is in the vineyard; Heidi is most comfortable in the cellar and lab.

"As long as we stick to those roles, it is possible to be married and make great wine together," Heidi said at a recent San Francisco dinner debuting the newest vintage of their joint venture, Barrett & Barrett, a 300-case, ultra-premium cabernet sauvignon they launched three years ago. The wine is available via mailing list at www.barrettwines.com.

Heidi is by all accounts the first lady of wine, a trailblazer responsible for some of the country's most sought-after and cult wines, from Screaming Eagle and Dalla Valle cabernet sauvignons to Amuse Bouche and her own elegant La Sirena wines.

Her husband, Bo, is head winemaker for Chateau Montelena. I've never had a bad or even mediocre Montelena wine. Bo has created a legacy with those European-style Chardonnays, and he does it all in the vineyard. The family calls him Farmer Bo.

After nearly 30 years of marriage and 70 years of combined winemaking experience, Heidi and Bo have united their individual styles -- her elegant, artistic sense of balance; his penchant for classic style and structure -- into an ageworthy cabernet. The current 2010 vintage is a stunner, with aromas and flavors of mint and blackberry jam and powerful tannins that will do wonders to shape the wine in years to come.

The project is truly a family affair. Daughter Remi, 27, handles trade accounts (and sales and marketing for La Sirena), and there are hopes that Chelsea, the Barretts' younger daughter, will eventually join the team. She currently makes wine for Joel Gott Wines.

"Remi nudges her every now and then to come join us," Bo said. "Her job is a lot different from mine. She makes in three weeks what I do in a year."

Now in its third vintage, Barrett & Barrett is indeed a small production. Its 300 cases of cabernet sauvignon are made from grapes grown on a vineyard planted on the couple's Calistoga property in 1989. Situated at the base of Mount St. Helena, the steep volcanic slopes yield tiny, concentrated berries.

The second cabernet blocks are found in a gravelly vineyard across the road from a longtime Chateau Montelena-farmed property. Bo had his eye on the property at the confluence of Garnett Creek and Jericho Creek for years and developed it specifically for this project.

"It is one of the very few areas in Napa Valley that are quite similar to the lands and weather patterns of Montelena, with which I had such a great experience," he says. "I just knew there was good dirt and great light, so we are stoked to have it in production now."

The project is a natural next step for a powerhouse couple, who has raised three children (their son, Seamus, attends law school in New York), developed four vineyards (two for La Sirena and now two for Barrett & Barrett) and learned to fly helicopters together. There are no plans to grow the label or add other varietals. They're happy keeping it small and in the family.

"In our business it takes a vineyard five years to mature, another two years of winemaking and then more time for bottle age," Bo says. "We don't do anything in a hurry."

Contact Jessica Yadegaran at jyadegaran@bayareanewsgroup.com. Follow her at Twitter.com/swirlgirl_jy.