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California’s Lead Women Winemakers Show Slow, Steady Progress from 2011 to 2020
Lucia Albino Gilbert, Ph.D. & John C. Gilbert, Ph.D.
Santa Clara University, Santa Clara, CA 95053

Do California’s women winemakers hold more lead winemaker positions in 2020 compared to 2011? In 2011, we reported that the figure was only 9.8%, far less than had been assumed. If so, what is that increase, and what wine regions are contributing to this progress?

  Nearly ten years have passed since our first study, "How Many Women?" California’s wine industry continues to grow, with the number of bonded wineries having increased from 3200+ in 2011 to 4200+ in 2020. At the same time, increasing numbers of women are studying viticulture and enology, and receiving mentoring and guidance within the industry. Are these changes reflected in the percentage of California wineries having women in lead winemaker positions?

Our 2020 Study
Similar to our first study, we used the official published list of bonded wineries made available by Wines Vines Analytics. Using the Wines & Vines 2020 Directory and Buyer’s Guide (http://www.winesandvines.com/) as the sampling frame, we selected 500 wineries at random from among the 4200 wineries listed for the state of California, a random selection that gives a 95% confidence level to our results.1 Public information (e.g., pronouns used in website profiles) and email/phone contact with the wineries were used to code a winery’s main or lead winemaker as female or a male or a female-male co-winemaking team. A winery’s location and production range were also coded.

The proportion of wineries by region was quite similar to our 2011 study of all California wineries, as was the pattern of their case production.2 As shown in Figure 1, just over half of the California wineries were located in the Napa Valley (33%) and Sonoma/Marin (21%) wine regions, with the South Central Coast region (San Luis Obispo and Santa Barbara Counties) being the third largest (17%).3 In the 2011 study, the percentages were 29% for the Napa Valley, 21% for Sonoma/Marin, and 15% for the South Central Coast region.

Figure 1. Percent of California Wineries by Wine Region

Evidence of Positive Change: Wine Region Matters
The good news is that summing across all of California’s wine regions, the percentage of lead women winemakers increased from 10% in 2011 to 14% in 2020 (see Figure 2). This represents a statistically significant increase.

Figure 2. Percentage of California Wineries with Lead Women Winemakers by Wine Region, 2011 and 2020.

Figure 2 also depicts the increased percentage of wineries with lead woman winemakers for two of the three large wine regions of California, a significant increase to 17% both for the Sonoma/Marin and South Central Coast regions. The percentage for the Napa Valley, the most well-known and largest California wine region, remained constant at approximately 12%. It should be noted that given the relatively small number of wineries in the regions other than the Napa Valley, Sonoma/Marin, and the South Central Coast regions in the random sample (see Figure 1), only the percentages for these three regions are presented separately in Figure 2.4

In interpreting these percentages, it is important to remember that the percentage of wineries with lead women winemakers is different from the number of women winemakers in a region. In calculating the percentages, the numerator is the number of wineries with women winemakers in a particular region and the denominator is the total number of wineries in that region. A large denominator obviously affects the size of the percentage. In the case of the Napa Valley, although the number of wineries with women winemakers (the numerator) was the highest numerically among the various wine regions, Napa also has the greatest number of wineries, so its denominator is the largest as well, and this resulted in the lower-than-expected 12% figure.

The Apparent Napa Puzzlement
Nonetheless, we were puzzled by these findings and considered various explanatory variables that could have affected the percentage we calculated. An explanation based on a greater increase in the number of wineries, and thus greater opportunities for women winemakers, in the Sonoma/Marin and the South Central Coast regions (San Luis Obispo and Santa Barbara Counties) is not supported, given that the growth in wineries appears to be somewhat proportional across all of the state’s wine regions. Family and corporate ownership appear similar across the three wine regions as well and thus are also not possible explanatory variables.

One category of winery ownership, however, could provide an explanation. First, as noted by Steve Heimoff in his recent farewell article in memory of Milla Handley,5 a trailblazing winemaker in the Anderson Valley wine region: "Most founding winemakers of the 1970s and 1980s were authentic startups, with little money but big dreams, as opposed to a later era, when the winery "lifestyle" became buyable by rich outsiders." The Napa Valley is in close proximity to Silicon Valley, where many entrepreneurs have made large fortunes, and investing in Napa’s wine industry may be attractive to those "rich outsiders." Second, Napa is expensive, more so than Sonoma/Marin and the South Central Coast, and is only affordable by those with considerable resources for investment in winery property and developing their own label. How, then, could these factors explain the lack of an increase in the percentage of lead women winemakers in the Napa Valley during this time period?

A review of male-only winery ownership among the wineries in our random sample revealed that the percentage of wineries having one or more male owners who were neither the winemaker nor part of multigenerational family ownership was much higher for the Napa region (19%) than for Sonoma/Marin (6%), and the South Central Coast (10%). Among these wineries, there were few lead women winemakers. As reported in our 2015 study, "Assessing Progress," men are hired more often than women when lead winemaking positions become available, particularly at non-family-owned wineries, most possibly due to an unconscious pattern of gender bias. Given women’s overall small numbers as lead winemakers, the pattern of hiring in this subset of wineries, many of which involve deep-pocketed entrepreneurs, could have suppressed the numerator while the increased number of male-only winery ownerships percentage could have increased the denominator.

Winemaking remains male-dominated in California, but progress in terms of the involvement of women is slowly but surely taking place. This study provides solid evidence for increased percentage of lead women winemakers in California, especially in the wine regions of Sonoma/Marin and the South Central Coast (San Luis Obispo and Santa Barbara Counties), and solid evidence of their continued presence in the Napa Valley.

Our first study, "How Many Women?," showed that only 9.8% of California’s 3200+ wineries have lead woman winemakers. "Evidence of Success," our second study, indicated that despite their small numbers in the industry, lead women winemakers are producing wines that are more highly acclaimed, proportional to their representation in the field, than wines produced by their male counterparts. "Assessing Progress," a third study that compared lead winemakers at the same set of major CA wineries at two different times, 1999 and 2015, found evidence for some increase in the percentage of lead women winemakers over that time period.6 This fourth study buttresses our earlier findings and reinforces the conclusion that change is slow but sure with respect to the increasing percentage of women holding the position of lead winemaker in California.


  1. Study results obtained from our random sample of 500 wineries drawn from the population of 4200 wineries has a margin of error of ±5% and a confidence level of 95%. The confidence level refers to how confident one can be that the actual sample values obtained in a study fall within the margin of error.

  2. With regard to case production, more than two-thirds of the wineries produced less than 5,000 cases per year, and 9% more than 50,000 cases.

  3. The wine regions are defined on the Women Winemakers and Beyond Website, http://www.womenwinemakers.com. Click on the California map on the home page of the web site to see definitions of the eight wine regions.

  4. The percentages for the smaller wine regions appeared quite similar to those we reported in 2011 for all California wineries. Just as in the 2011 study, the percentages varied somewhat by wine region, and with the exception of Mendocino, all the percentages were quite low.

  5. http://www.steveheimoff.com/index.php/2020/08/04/milla-handley-gone-to-the-winery-in-the-sky/

  6. The three studies are posted on our website under the heading, Book/Studies.

Author Bios: Lucia Albino Gilbert, Ph.D., and John C. (Jack) Gilbert, Ph.D., both professors emeriti, have had long and distinguished careers at The University of Texas at Austin and Santa Clara University and are widely published in their fields. Their research on facilitating women's career success in male-dominated scientific fields such as winemaking combines Lucia's academic field of Psychology and John's academic field of Organic Chemistry. They can be reached at lgilbert@scu.edu. Their research website is www.womenwinemakers.com.

Posted September 2020