Beware, hop lovers: a warming climate could make your IPA less bitter.
In recent years, hop yields have been declining in Europe, as has the concentration of alpha acids in hops, which give beer its bitter taste, a study published last week in the journal Nature Communications finds. The study authors also predict that hop yields and alpha acid content will continue to drop in the region in the future.
“Beer drinkers will definitely see the climate change, either in the price tag or the quality,” Miroslav Trnka, a co-author of the study and bioclimatologist at the Czech Academy of Sciences, tells the Guardian’s Ajit Niranjan. “That seems to be inevitable from our data.”
“With climate change affecting a vast number of agricultural crops, I’m not surprised,” Douglass Miller, a food and beverage management expert at Cornell University who did not contribute to the findings, tells CNN’s Rachel Ramirez.
Brewers have been creating beer in central Europe for over 5,000 years, according to the paper. Hops, the green, cone-shaped flowers of the Humulus lupulus plant, give beer its bitterness, aroma and flavor. The alpha acid content in hops affects their quality, and the recent surge in the popularity of craft beers and brews that rely on high-quality hops, the study authors write. But hops can only grow in specific regions where the environmental conditions are just right, making them vulnerable to heat waves and droughts.
“If you look at the map and where the hop growing regions are, you’ll see them in a fairly narrow band of latitude,” Chuck Skypeck of the Brewers Association tells the Washington Post’s Maggie Penman. “They’re very light sensitive.”
The researchers wanted to look at how climate change is affecting and will continue to affect the quality and quantity of hops across Europe. They first measured how hop yields and alpha acid content changed over the last five decades, comparing the average annual crop yields from 1971-1994 to those from 1995-2018. They observed as much as a 19 percent decline in some regions of Europe. In those same time spans, the alpha acid content dropped between 0.5 and 1.9 percent.
Scientists aren’t exactly sure why alpha acid production is declining, but it could be because the plants are growing earlier, writes Wired’s Matt Simon. The researchers also found that with temperatures rising, the hop growing season started 13 days earlier in 2018 compared to 1970.
To see what effect climate change could have on future hop production, the researchers analyzed the relationship between precipitation, temperature, sunshine duration and hop production in the past, then used statisical models to project forward. The model predicted that hop yields would decline between 4 and 18 percent between 2021 and 2050 compared to average yields between 1989 and 2018, and that alpha acid content would also decline between 20 and 31 percent. The main cause of these predicted drops were anticipated increases in temperature and more frequent and severe droughts.
“One of the side motives of this study was to illustrate how climate change might be important for even those who think it doesn’t matter,” Trnka tells CNN. “We are really seeing changes that are affecting things that we value, like the taste of beer. Climate change really can have an effect on it, or at least have an effect on commodities that are critical for production.”
Europe’s hops are more vulnerable to drier conditions than hops in the U.S., where more extensive irrigation keeps the water coming, Maggie Elliot, science and communications director at the Hop Growers of America, tells Wired. Hop farmers have also responded to climate change with strategies like moving gardens to higher elevations, building irrigation systems and changing the orientation of crop rows, per the study.“Adaptation is possible, but only if you keep warming to a reasonable level,” Trnka says to the Washington Post.