UC Davis Students Brew a Banana Beer for Sale

UC Davis researchers and students turned a class project into a commercial beer this spring, using fermentation science, recipe adjustments and scale-up work to produce Bananaweizen, the winner of the university’s 2026 Iron Brew competition.

The beer began as part of FST 102B, Practical Malting and Brewing, a course in which students at the Robert Mondavi Institute for Wine and Food Science develop recipes and brew test batches in the pilot brewery before competing for the chance to have their beer made for sale. The winning beer was then brewed at Dunloe Brewing in Davis, Calif., after the team worked with the brewery to adapt the recipe from a pilot batch to a 16-barrel commercial system.

Bananaweizen is a Hefeweizen, a wheat beer style known for its cloudy appearance and yeast-driven fruit and spice notes. In this case, the beer was designed to emphasize banana aroma, with clove and mild spice in the background. The team said the flavor came from careful control of mash temperatures, fermentation conditions and post-fermentation handling.

The students behind the beer were Christopher Chiu, Amber DePry, Humberto Gonzalez Loera and Kaylianne Jordan. Chiu brought prior hands-on brewing experience from UC Davis’s campus brewery, while the others came from viticulture and enology training. Together, they worked through three mash steps: a protein rest at 44°C to help foam stability, a rest at 63°C to convert starches into fermentable sugars, and a mash-out at 72°C to hold the sugar profile in place.

After nine days of fermentation, the team used a CO₂ blow-off to remove some sulfur compounds that had developed during fermentation. That step helped bring forward the banana character they wanted in the finished beer. Judges later noted some sulfur remained and said the banana aroma was less pronounced than the name suggested, but Bananaweizen still won by less than a point.

The move from student recipe to commercial production required more changes. Brennan Fleming, co-owner of Dunloe Brewing and a UC Davis alumnus, reviewed the formula before brew day and helped reduce the proportion of wheat malt so it would work better on his system. The brewery also added ALDC to help prevent diacetyl formation during fermentation and Clarex to reduce haze. Those adjustments were aimed at keeping flavor stable and improving consistency at larger volume.

On brew day, all four students worked alongside Fleming as grain moved through the roller mill, mash tun, kettle and heat exchanger. The brewery said that kind of scale-up is not simple because small changes in ingredients or process can affect body, clarity and flavor once a recipe moves from pilot equipment to commercial tanks.

The label for Bananaweizen was created by a local artist through Dunloe’s drawing club, part of an effort by the brewery to connect each release with community artists. Dunloe has also hosted events such as Gorilla Queer Bar nights and drag shows and has brewed solidarity beers including “Black is Beautiful.”

Bananaweizen is being poured at Sudwerk Brewing Co., The Gunrock and Dunloe’s The Local in Davis while supplies last.