Hop research: Study at Oregon State shows soil type, location impacts hop flavor profile

Oregon State hop research — Anecdotal reports from the event affirmed the sensory panel’s conclusion that the beers have distinctively different characteristics.

Scientists at Oregon State University’s College of Agricultural Sciences (OSU) and Red Hill Soils, along with farmers from Oregon’s largest hop grower, Coleman Agriculture, recently shared the initial findings of a year-long study into the effects of terroir on the flavor profile of hops, a primary ingredient in beer. The preliminary findings were presented at the Coleman Hop Terroir event in one of Coleman Agriculture’s hop yards near Independence, Ore., to a select group of industry professionals, including brewers, industry professionals, media, scientists and neighboring farmers.

Attendees were the first to hear about the approach to the study and the initial results: Yes, there is a measurable, perceptible difference in the beers brewed from hops grown in different locations and soil types. This work is the first step toward determining exactly how to manage the crop to produce the most desirable hops with specific traits.

“Growing hops and brewing beer are each an intricate blend of science and art, and we know intuitively that the flavor of hops can vary from field to field, and that some beers have a distinctive taste that could only have been created by hops from a specific yard,” said John Coleman, farmer and partner at Coleman Agriculture. “This study validates what so many of us farmers and brewers have instinctively known — that there are differences, and that they matter. But now we’ve started to learn why those differences exist.”

Study details

For the purpose of the study, terroir is defined as the unique soil composition, climate and cultural practices that may impact the flavor and aroma of hops.

The project examined two different varietals of hops, Sterling and Centennial, grown across four different locations in the Willamette Valley and two main types of soil. Scientists analyzed the physical and chemical characteristics of the soil, the climate and weather conditions over the course of the growing season, the crop management techniques employed and the chemistry of the hops grown there. A sensory panel was conducted to evaluate perceptible differences among the beers brewed with hops from each location studied.

“The most important thing we learned is that terroir does measurably affect the hops,” said OSU Professor of Fermentation Science Dr. Tom Shellhammer, who led the scientific team’s efforts. “There are differences in soil, climate and hop chemistry, and we can even taste the difference in the beers brewed from these hops. In this study, we found that the differences between Sterling hops from different locations were more muted and nuanced, and in the Centennial hops the differences were clearer and more easily identifiable.”

Guests at the Coleman Hop Terroir event were offered samples of the study’s beers under a tent located in one of the yards featured in the study. Anecdotal reports from the event affirmed the sensory panel’s conclusion that the beers have distinctively different characteristics.

“This isn’t the end of the story, it just verifies that there is something there worth investigating,” added Dr. Shellhammer. “The next part of the journey is to dig deeper, both metaphorically and literally, to find out what drives these differences and how we can manipulate them to achieve specific results.”

Coleman Agriculture and OSU will release the full study results publicly in late 2019 and have announced their intent to launch the second phase of the study in the months ahead.

“This is only the beginning of an exciting movement for the entire beer industry, with the potential to benefit hop farmers, brokers, brewers and beer enthusiasts worldwide,” said Liz Coleman, Terroir Project Lead. “The work we’ve done here is a great example of all boats rising with the tide. Together, as those of us in the industry continue to learn and share research into terroir’s impact on hops, we will position Oregon as one of the world’s premier sources for high-quality hops and brews. And that’s good for everyone who loves beer.”

The Coleman Hop Terroir Team is composed of the following people: