After rifling around in his bag, Teryn Citino strikes paydirt. With his long hair pulled back in a bun, Citino lights a crumpled paper fuse and touches it to the propane burner, igniting a blue flame that will eventually turn 6.6 gallons of garden-hose water into a heady homemade beer.

In a Somerville driveway, surrounded by gleaming stainless-steel tanks and flasks of golden-orange yeast, a group of highly educated bio-hackers confronts one of the most vexing questions in engineering.

Not just any beer. Citino and his cohorts in this daylong experiment are employees of Ginkgo Bioworks, a Boston company that tinkers with the genes in microorganisms, transforming everyday yeast and bacteria into living factories capable of pumping out unusual compounds.


They’re making three batches of homebrew for the company’s upcoming office-warming party, a project that combines the company’s scientific pedigree with the knowledge of a few employees who make their own beer at home.

One beer will use a commercial yeast that any homebrewing hobbyist could buy. A second was cultured from an apple at a nearby orchard, swabbed by a Ginkgo employee on the hunt for new strains.

The third variety, however, is the real star: It was created in Ginkgo’s lab, where scientists modified yeast genes to produce valencene, a natural flavoring that supplies a citrusy scent. (Although Ginkgo is giving away its employees’ homebrew, the company notes that it’s technically possible to use FDA-approved genetically modified yeasts to produce commercial beverages, including wine.)

It’s an ultra-geeky detail that separates Ginkgo’s office brew from the tap handles you’d find in the office kitchen of any other hip tech startup.

“Our work is all about fermentation,” says Christina Agapakis, Ginkgo’s creative director. “It’s not like we’re bros and we drink all the time. It’s more that beer is a really interesting phenomenon.”


Scientists modified yeast genes to produce valencene, a natural flavoring that supplies a citrusy scent. Keith Bedford/Globe staff

The GMO beer experiment also reveals an affinity for fermentation that runs throughout the company.

Ginkgo’s director of fermentation engineering, Emily Greenhagen, is also co-owner of Mystic Brewery, a craft beermaker based in Chelsea. And Prakash Iyer, the Ginkgo engineer leading the driveway brew, actually joined the company’s fermentation unit after mentioning in his job interview that homebrewing was one of his hobbies.

“My friends dragged me into it, and I got really geeked out about the science of it,” Iyer says. “Then I got into fermentation, so I went even further.”

As a side benefit, the modified yeast produced at Ginkgo could actually make the homebrew recipe cheaper. That’s because the strain produces the kind of flavor and aroma chemicals, called terpenes, that are usually only found in plants — in this case, the aromatic hops that can fetch a pretty penny at homebrew supply shops.

After about five hours of stirring, boiling, measuring, and pouring, the half-dozen Ginkgo employees clogging Agapakis’s driveway are still working on their first batch. Once this phase is done, the beers will sit for about two weeks in the fermentation tanks before they’re ready to be kegged and carbonated.

Teryn Citino (left) and Prakash Iyer filtered their beer during the brewing process. Keith Bedford/Globe Staff

“A lot of brewing,” Iyer says, “is waiting.”

Things are moving a lot faster at Ginkgo’s offices in South Boston’s marine industrial park. The company, which raised $100 million in private investment this summer, is hiring like mad and expanding into a second lab space.


The startup is also busy finding commercial partners for its technology, including Amyris Inc., a giant industrial bioproducts company that is partnering with Ginkgo to develop products such as flavorings, fragrances, cosmetics, and nutritional additives.

“Biology is just an incredible way to make stuff,” Agapakis says. “I mean, just look around. I think we really take it for granted.”

Curt Woodward can be reached at curt.woodward@globe.com. Follow him on Twitter @curtwoodward.