Whether you like lagers or extra-bitter IPAs, you like alpha acids and just don’t realize it. These are the compounds in hops that impart that bitter taste, which could be subtle or intense, depending on the cultivar. For centuries, farmers who produce hops for traditional European beer making—particularly in Germany, the Czech Republic, and Slovenia—have honed that alpha acid content. More recently, farmers within the Pacific Northwest of the US have done their very own honing, producing hops with the characteristic aromas that make West Coast IPAs citrusy and juicy.
But now, climate change is seriously mucking with hops. Droughts and extreme heat have already reduced yields, in addition to the alpha acid content of hops grown in Europe. And recent modeling, published last week in Nature Communications, estimates that by the yr 2050, Europe’s hop growers will see an extra 4 to 18 percent drop in yields and a 20 to 31 percent drop in alpha acid content. “What we’re seeing under climate change is a mixture of more droughts that can affect the yield of the plants, unless irrigation is supplemented,” says bioclimatologist Mirek Trnka of the Czech Academy of Sciences, a coauthor of the brand new paper. “At the identical time, higher temperatures are usually not conducive to high alpha acid content.”
Lower yields and a drop in acid content could change into a compounding threat, says Oregon State University hop chemist and brewing scientist Tom Shellhammer, who wasn’t involved in the brand new paper. If the hops are harvested with 30 percent less alpha acid content, “meaning you should use 30 percent or more of that hop,” says Shellhammer. “If the actual yield that has been produced on the farm is down,” he adds “then there’s just less of it available inside the industry. So the brewery would must use more of it. That then creates a supply issue.”
Generally speaking, brewers and farmers—be it for hops, barley, or malt—are still parsing how a changing climate is changing beer. There are overlapping aspects. In addition to rising global temperatures and fiercer droughts that cause water scarcity, there are more extreme heat waves, plus attendant problems like larger wildfires that may spoil crops with smoke. (The wine industry is facing related issues with grape production.) “We still don’t properly understand the extent of impact climate change could have, particularly on minor components that contribute to flavor,” says Glen Patrick Fox, who studies brewing and beer quality at UC Davis. “This will probably be a case of the industry having to maintain measuring things for quite a time frame to actually understand how that can occur.”
Farmed on a trellis system, hop plants can tower 20 feet, producing the cones that give beer complex flavors and bitterness. But higher temperatures reduce alpha acid production in those cones. The reason isn’t yet clear, but it surely could possibly be a consequence of them developing earlier within the season. In Europe, they now appear about three weeks sooner than they did in 1994. Higher temperatures are having an analogous developmental speedup on cereal crops.
“They simply don’t have enough time to supply all of the priceless chemicals—or in case of grain, prepare enough starch,” says Trnka. “That could be a mechanism for the hops, or there could be one other mechanism that’s related to a specific biochemistry. But we don’t know that yet. It’s been fairly elusive.”