The cultivation of aromatic hops in Europe, particularly popular for craft beers, is being disrupted by climate change, reducing yields and concentrations of the chemical compound responsible for bitterness, according to a study published Tuesday in the British journal Nature Communications.
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Researchers observed this trend by analyzing data from five locations in Germany, Slovenia and the Czech Republic, which, along with Poland, are the main hop producers in Europe, said Miroslav Trnka, one of the study’s co-authors.
At four locations, yields fell from 9.5% to 19.4% in the period 1995–2018 compared to the period 1971–1994 and remained stable at a fifth location.
At the same time, rising temperatures have advanced the main stages of hop development by several days, affecting the concentration of alpha acids, the compound in hops that gives beer its bitterness and certain other flavors.
By extrapolating this data, researchers predict a 4% to 18% decline in hop yields for the 2021-2050 period compared to the 1989-2018 period and a 20% to 31% decline in alpha acid content.
Across southern and central Europe, “it will be necessary to increase the area under cultivation of aromatic hops by 20% compared to the current area in order to compensate for the future decline in alpha acid concentration (and/or hop production),” the study says.
Hop farmers, an essential ingredient in beer along with malt, water and yeast, have taken steps to adapt.
But the cultivation options themselves are limited because the plant requires “a specific combination” of climate and soil, notes Miroslav Trnka.
It is also not possible to advance the harvest too far, while the introduction of genetically modified crops to improve resistance to climate change is banned in Europe, he says.
Brewers can certainly modify their manufacturing processes to take advantage of the bitterness.
But the researchers in the study are primarily calling for “urgent adaptation measures,” such as relocating plantations within a region, irrigation or shading, explains Miroslav Trnka.
Nature Communications is part of the same group as the famous scientific journal Nature.