Do you love me or not? Lager or extra bitter IPA, you love alpha acids, but you just don’t know it. These are compounds in hops that give them a bitter taste, which can be subtle or intense depending on the variety. For centuries, farmers producing hops for traditional beer making in Europe, particularly Germany, the Czech Republic, and Slovenia, have honed alpha acid content. These days, farmers in the U.S. Pacific Northwest do their own honing to produce hops with the characteristic aroma that makes West Coast IPAs citrusy and juicy.
But now, climate change is having a serious impact on hops. Drought and extreme heat are already reducing yields and the alpha acid content of hops grown in Europe. And new modeling published last week nature communicationspredicts that by 2050, European hop growers will see a further 4 to 18 percent reduction in yield and a 20 to 31 percent reduction in alpha acid content. “What we are seeing under climate change is that unless irrigation is replenished, further droughts will compound and impact plant yields,” said Czech, co-author of the new paper. says Mirek Trnka, a bioclimatologist at the Academy of Sciences. “At the same time, higher temperatures do not result in higher alpha acid content.”
Lower yields and lower acid content could be a combined threat, said Tom Shellhamer, a hop chemist and brewing scientist at Oregon State University who was not involved in the new paper. If a hop’s alpha acid content is harvested with 30% less, “that means you need to use 30% more of that hop,” Shellhamer says. “If the actual yield produced on the farm is reduced, it will only reduce the amount available within the industry,” he added. Therefore, breweries need to use it more. That creates a supply problem. ”
Brewers and farmers in general are still figuring out how changing climate is changing beer, whether it’s hops, barley or malt. There are overlapping factors. In addition to severe droughts that are causing global temperatures to rise and water scarcity, we are also seeing an increase in extreme heat waves and accompanying problems such as massive wildfires that destroy crops with smoke. (The wine industry faces challenges related to grape production.) “We still don’t know exactly how much impact climate change is likely to have, especially on the trace components that contribute to flavor.” They don’t understand it,” says Brewing and Beer Researcher Glenn Patrick Fox. University of California, Davis Quality. “This is going to be a case where the industry needs to keep measuring things for quite some time to really understand how it happens.”
Hop plants grown in trellis systems can grow up to 20 feet tall and produce cones that give beer its complex flavor and bitterness. However, higher temperatures reduce the production of alpha acids in those cones. The reason is not yet clear, but it may be a result of early season growth. It is now happening in Europe about three weeks earlier than in 1994. Rising temperatures are speeding up grain development as well.
“They don’t have enough time to produce all the valuable chemicals, and in the case of grains, they don’t have enough time to prepare enough starch,” Trnka says. “It could be the hop mechanism, or there could be another mechanism related to specific biochemistry. But we don’t know that yet. It’s been pretty elusive.”
