Today at Berkeley Lab

JBEI Researchers Harness Power of Microbes for Work and Winemaking

— By Keri Troutman


Scientists Chris Petzold (left) and Trent Northen have put their doctorates in chemistry to work in their JBEI research and in their free time, where they’ve applied their interest in the science of soil, plants, and microbes to wine making. The results thus far have been impressive and enjoyable.

“We’re both interested in analytical chemistry and understanding how microbes are behaving related to changes in environment—what they like to eat out of complex mixtures and turn into biofuels,” says Northen, a principal scientist who studies metabolic processes in the Life Sciences Division and in the Technology Division at JBEI. “When you smell wine and taste wine, you’re capturing these small molecules that have either been produced by the plant or the microbe.”

Backyard_WinemakingFor the past four years, Northen and Petzold have put molecules to work in their home-based wine making project. Both scientists are very interested in microbial communities in their work, and they make the connection that microbial communities are also what they’re using to make wine.

“It’s kind of like we’re harvesting the power of microbes to do different things,” says Northen. “At JBEI we’re using them to make biofuels and at home to make wine.”

Petzold’s interest in wine goes back to his graduate school days at Purdue, when he took an elective course on wine. He was hooked, and when he came to UC Berkeley for his post-doc he enjoyed the proximity to Napa and Sonoma for weekend wine-tasting trips. Those trips led to a seasonal job helping out at a small Sonoma family winery, Siduri Wines, where he experienced the full wine-making process. Through them, Petzold met some of the other Sonoma winemakers and pretty soon he was purchasing grapes for home experimentation.


When Petzold, who focuses on proteomics research in the Technology Division of JBEI, met Northen and let him taste a Syrah he had made, the wine making became a joint venture. The two now regularly wait for their September phone calls from grape growers and then head up to Napa or Sonoma with Northen’s truck ready to take delivery of hundreds of pounds of grapes.

“It’s tricky because when those grapes are ready, we have to jump on it and it doesn’t always line up with work and travel schedules,” says Northen.

After that, the fun has only begun. The two scientists sometimes crush the grapes on site, but often turn it into a family affair (both have young children) and let the kids help crush and sample the fresh juice. Then it’s into the fermenters (which Northen describes as “glorified trash cans”) and down into the crawl space under Northen’s home or into Petzold’s garage for fermenting and aging. The two have often collaborated with third JBEI scientist and fellow wine maker, Ben Bowen.

Sauvignon_Blanc_fermenting“The aging process is the part I like the most,” says Petzold. “It’s very interesting to see how it changes and how tastes differ.”

The first year they picked their own grapes—300 pounds of them—and made about 100 bottles of nice Petite Sirah. Last year it was 800 pounds of a lovely Sauvignon Blanc. They’ve also made Zinfandel, Pinot Noir, and Cabernet Sauvignon. Their fellow LBNL wine maker, Bowen, sticks to his favorite, a tried-and-true Petite Sirah, and he’s focusing on getting a solid formula down on which vineyard and yeast and process produces the best wine.

“We are experimenters and we make different mistakes every year,” jokes Petzold. “Our goal is to not make the same mistake.”

They describe the wine-making investment as pretty minimal, both financially and in terms of time—they rent or borrow a lot of equipment and most of what they have bought (besides the grapes) has been under $100. There’s a big push at grape harvest time, but then it’s mostly a wait and see approach throughout the winter, with some minimal checking in. In spring, the best part comes with bottling and tasting the product.

“It’s really intriguing; there are so many options at each step and each decision send the wine down a different trajectory,” says Northen. “Unfortunately there is no undo button”