Why? Hard to say and that's not a question the Gilberts attempt to answer in this study but it may have something to do with persistence. It takes the same effort and skills for a male or female winemaker to succeed, but women can face additional challenges achieving success in a male-dominated field.
"I think women winemakers had to be really determined and really passionate and still do," says Corison, named 2011 Winemaker of the Year by the San Francisco Chronicle.
An academic psychologist who has studied women's career paths, Lucia Gilbert became interested in women winemakers. With little information available on the subject, she put together a comprehensive list of the 3,200-plus winemakers in California, identifying the women and developing the website, Women Winemakers of California.
The total of women winemakers came to 9.8 percent, below the 15 percent to 20 percent the Gilberts expected.
It's easy to see why she overestimated. After all, some of the most famous winemakers are women, such as Heidi Barrett, who worked for the "cult" winery Screaming Eagle. Among other kudos, the winery is known as home of a 6-liter bottle of the 1992 vintage that sold for $500,000 at the 2000 Napa Valley Wine Auction.
So, the researchers came up with a new question are women winemakers achieving disproportionate levels of success?
Quantifying winery acclaim is a slippery business, but the Gilberts went at it by using the listing of wineries from the 2010 reference work Opus Vino, which includes about 4,000 wineries in the world identified as noteworthy by wine critics and wine writers who worked with the book's editor-in-chief, Jim Gordon.
The results were that 23 percent of California wineries with women winemakers made it into Opus Vino, compared with 14 percent of wineries with male winemakers.
Gordon, former managing editor of Wine Spectator magazine and today the editor of Wines & Vines Magazine, was surprised by the Gilberts' findings. He and the other authors picked out top wines based solely on quality and without regard to the winemakers behind them, so "seeing our selections through the perspective of Dr. Gilbert's data was a kind of revelation."
But Gordon's not convinced that women winemakers are disproportionately successful given the 10 percent baseline. "There is still a long way to go there," he points out.
Are there differences between women and men winemakers?
Corison used to resist that idea "with everything I had. Because differences have always been against women."
But after years of working in the field she feels that there may be two differences. "There's pretty good evidence that women have perhaps better sensory abilities. So that's one issue. And, I believe that winemaking is all about details. So perhaps if there's a difference in attention to details? I don't know. I don't feel strongly about that."
Corison, who grew up in Southern California, took a roundabout path to winemaking.
She studied biology, but "fell in love with wine when I was a sophomore." She was smitten by "all the usual reasons, it's delicious, you share it with friends, it makes food taste better and vice versa. On another level, I fell in love with the fact that it's a whole series of living systems. I'm a biologist and I'm still studying biology. That's what tunes me into winemaking, the fact that it's alive."
"There have always been challenges, but I think there have been advantages, too. I think that we sort of stuck out like sore thumbs, so for better or worse people noticed what we did," Corison says of women in her field.
Study is online
O Go to http://www.womenwinemakers.com