Hops used to grow abundantly in the Netherlands. Local brewers used it to preserve their beer. Could this flower be reintroduced on a large scale as a true flavor enhancer for special beers? Hollands Hophuis asked researchers and Inholland University of Applied Sciences students to see whether hops could find a permanent home in greenhouses. On Monday, June 13, at the closing symposium, you can see, hear, and taste the results. Registration is still open.
Hops are to beer what grapes are to wine. Depending on things like soil type and the climate, each hop plant adds a distinctive flavor - 'terroir' - to the drink. Carel Krol is an expert on this subject. As co-founder of Hollands Hophuis, he shares his knowledge of hop growing and the wide variety of hops with beer brewers. Most hops are grown in Europe, yet there is no Dutch variety.
Hollandse Hop's RAAK SME research project
"Hop grows well in the Netherlands, but you don't find any sufficiently flavorful, aromatic hops here," says Carel. "Nevertheless, we wanted to investigate whether it's possible to cultivate Dutch hops for local beer brewers." Inholland took this request and set up the Hollandse Hop RAAK SME research project with Wageningen University and Research (WUR), the Naturalis Biodiversity Center, Hogeschool Leiden, and several other companies.
Looked at DNA, flavor components, and cultivation
The project consisted of several studies. An inventory was made of the hops that can still be found in the Netherlands. Researcher and lecturer Maaike Boersma of Green Biotechnology and her students compared the DNA of hop plants from the Naturalis herbarium with wild hop plants. Chemical researcher Niek van Leeuwen helped with the flavor component analysis. Horticulture and Agribusiness' Frank van der Helm, also a researcher and lecturer, worked with his students on optimizing new hop plant cultivation methods.
Growing hops in a greenhouse
These methods focused on greenhouse cultivation - a new environment for hop plants. "More and more Dutch greenhouses are becoming vacant," says Nelleke Kreike, lecturer in Green Biotechnology. "Hop cultivation could be a nice alternative to growing tomatoes and bell peppers; crops that also grow vertically. The advantage of greenhouses is that you can control the conditions very well and thus increase the yield."
Second and third-year students did the research
Inholland students were involved in the project in various ways. "Second- and third-year Biotechnology students used new techniques and devices to analyze the hop plants' DNA," she says. "Those doing Horticulture and Agribusiness worked with new cultivation methods."
"They did that in WUR's Glasshouse Horticulture's greenhouses. They monitored the different hop varieties' growth and recorded the climatic conditions. Thus, all these students were answering practical questions and advancing their profession. They used techniques that are completely new in the field," Nelleke explains.
During interactions like guest lectures, Carel saw that the students were very excited to work on this project. "I told them about hops, what it is, and where it originates. The students were really interested and asked great questions." Carel is also pleased to be working with the college. "The project is about applied research based on a concrete question. That will ultimately result in new knowledge we can take to companies."
What has the Hollandse Hop project yielded? "We've shown that hops grow well in a greenhouse. The cultivation's efficiency still has to be tweaked, though. The sharply increased gas prices, which make greenhouse cultivation expensive, complicate things. But perhaps sustainable heating methods could solve this in the future," Carel says.
Monday, June 13: Hollandse Hop symposium
Are you curious about the development of the new Dutch-grown hop? Would you like to know the genetic composition of historical and current hop plants? Are you interested in what this research reveals about the importance of preserving the Dutch cultural landscape? Then come to the Hollandse Hop symposium at the Naturalis Center in Leiden on Monday, June 13. You can taste a locally-brewed special beer.