This Marin County blog post highlights the remarkable story of Ed DeMayo, an 80-year-old San Rafael retiree who captured best-of-show at the 31st World Cup of Beer with his science-inspired brewing-sausalito/”>saison, “I Am Science.” From a kitchen bench in Greenbrae to a nanobrewery tucked beneath his San Rafael home, DeMayo’s journey shows off the hands-on, community-driven spirit that really defines Marin’s homebrewing scene.
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Marin County’s homebrew hero: Best-of-Show at the World Cup of Beer
The Bay Area Mashers competition drew 335 entries. DeMayo’s saison not only claimed best-of-show but also topped the strong Belgian ale category.
His lambic “Zoonotic” earned the top spot in the sour beer category. A lot of Marin fans compare his range of skill to the early days when craft beer first exploded across Sausalito, Mill Valley, and Larkspur.
In San Rafael, Greenbrae, and Terra Linda, neighbors followed the news with pride. The Bay Area’s homebrewing community nodded to local innovation.
DeMayo’s win marks a milestone after a lifetime tinkering with grain, yeast, and timing. He formed his tiny Brewers’ lab, Brewery 42, with his son Nick as a bonding project during Nick’s grad school years.
What started as kitchen batches in Greenbrae evolved into a dedicated nanobrewery under DeMayo’s San Rafael house. That setup has become a fixture in Marin County’s brewing lore.
The Brewery 42 story: science, siblings, and a basement lab
DeMayo studied biology and chemistry as an undergrad and spent decades as a surgeon in Greenbrae and Terra Linda. He approaches brewing like a research project, always chasing that next experiment.
He talks about the chemical challenge of converting grain starches into fermentable sugars. There’s a careful balance to coax complex flavors from slower yeasts—those can develop more nuanced character over time.
He points out that homebrewing lets him pick ingredients and control timing. Commercial breweries, he says, don’t have that kind of freedom.
After retiring five years ago—following 30 years in private practice and a final decade at Kaiser in Terra Linda—DeMayo has stayed put in the same San Rafael house for fifty years. The name Brewery 42 even nods to The Hitchhiker’s Guide to the Galaxy, which says a lot about his playful approach to science and storytelling.
He’s always experimenting with new strains, fermentation schedules, and aging profiles. Sometimes, he admits, things don’t go as planned, but that’s part of the fun.
- I Am Science is a saison that earned best-of-show and first place in the strong Belgian ale category. It really shows off the range of DeMayo’s craft in Marin’s beer scene.
- Zoonotic, a lambic, won the sour beer category. That win highlights his willingness to push beyond the traditional American pale ales that once defined much of Marin’s early craft-brew culture.
- He relies on slower yeasts and patient timing. It’s a deliberate contrast to the quick-turnover commercial models that dominate some Bay Area breweries around Sausalito and Tiburon.
- For DeMayo, brewing stays a hobby focused on experimentation and community—not expansion. That philosophy resonates with longtime Marinites in San Anselmo and Corte Madera who love those local, intimate beer gatherings.
- Free Beer Friday has become a neighborhood ritual in San Rafael. It deepens connections with neighbors and reinforces the social role of homebrewing in Marin County towns.
A life devoted to craft, family, and community in Marin
DeMayo’s story is as much about family as it is about fermentation. The Brewery 42 project pulled him closer to Nick and really echoes a broader Marin tradition—grandparents, parents, and kids all sharing some passion in places like Novato’s boulevard cafés or the parks near Sausalito’s waterfront.
He isn’t interested in going commercial. Still, his work has nudged neighbors from Mill Valley to Corte Madera to try their own brewing experiments, weaving a sense of shared culture that keeps Marin’s beer scene small and pretty friendly.
This region’s known for its scenic drives from Tiburon to Santa Venetia, and those close communities in San Rafael and San Anselmo. DeMayo’s story quietly reminds you that sometimes brilliance just hides in the basement—a stainless-steel kettle, a lab notebook, a stopwatch, and a stubborn curiosity.
For Marin County folks who really savor that taste of place, Brewery 42 sticks around as proof that science and family can rise together, one bottle at a time.
Here is the source article for this story: Retired Marin surgeon’s home brew wins prestigious award
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