According to a study, climate change will increasingly cause problems for hop farmers in the important European growing regions in the coming years. Both the amount of hops harvested and their content of alpha acid, which is crucial for the beer's bitter note, will be significantly lower on average than before. The international team, which published its evaluation in the journal "Nature Communications", is therefore calling for "immediate adaptation measures" and considers larger cultivated areas to be necessary.
The five growing regions examined include Hallertau and Spalt in Bavaria as well as Tettnang in Baden-Württemberg. There are also two regions in the Czech Republic and Slovenia. On average (median) from 2021 to 2050, researchers expect roughly a third less alpha acid per hectare of cultivated area in these areas than in the period 1989 to 2018. In the Hallertau - the most important European growing region - it is even almost 40 percent.
As a starting point for the forecast, the team led by Martin Mozny from the Czech Academy of Sciences in Brno compared the harvests from 1971 to 1994 with those from 1995 to 2018 and had already noticed significant declines. The researchers attribute this particularly to increased temperatures and lower rainfall. These results were then projected into the future using climate models.
Are climate-tolerant hops already available?
The study has been partially criticized by local hop experts, but the fundamental problem is well known. “This is consistent with our practical experience,” says Erich Lehmair from the Association of German Hop Growers, for example. The harvest was also poor last year.
Anton Lutz from the Hop Research Center in Hüll, Bavaria, confirms that climate change "represents a major problem" for the hop plant, but one of his criticisms of the study is that changes in the variety spectrum were not taken into account. Breeding has already responded to the looming climate change: older varieties are almost being “overrun” by climate change, while the new varieties from Hüll are “much more climate tolerant”. A fact that Lehmair also addresses: In addition to the increased use of more climate-tolerant varieties, he also mentions irrigation as a countermeasure.
Climate protection is a priority
"Of course, climate change does not ignore hop cultivation," says Klaus Kammhuber - who, like Lutz, works at the hop research center. Ultimately, everything depends on whether climate change is slowed down or worsened, he emphasizes. That’s why climate protection must be an absolute priority.
The world's largest hop dealer, BarthHaas from Nuremberg, on whose data the study is partly based, is also observing the consequences of climate change for the plant and its cultivation. He firmly believes that it will be possible to maintain the competitiveness of hop cultivation in southern Germany with new varieties and cultivation methods, says managing director Thomas Raiser. It is not for nothing that 65 million euros have just been invested in an extraction plant in the Hallertau.