Higher temperatures and less rainfall are causing a decline in European hop yields. In addition, experts are concerned about how changes in the plant itself affect its flavor. This is evidenced by the analysis of half a century of hop harvesting conducted by Czech scientists in the trade journal Nature Communications. In the period 1970-2018, European hop growers’ harvests declined significantly. In addition, the concentration of alpha acids in the plant, the molecules that provide bitterness to beer, declined during that period. This is important for all types of beer, but especially for popular specialty beers, such as India Pale Ale.
Climate change will make the situation worse, scientists conclude with a model estimating the state of hop cultivation in 2050. Researchers fear that total alpha acid production will be 25 to 40 percent lower than it currently is.
Martin van Ittersum, professor of plant production systems at Wageningen University and not involved in the new study, talks about “solid modeling work.” He points out that high temperatures and frequent droughts cause plants to flower early. “Growing hops for beer revolves around lots of good hop cones – the flowers – and develops best after the longest day of the year. Very rapid development results in modest flowering, and growth is also hampered by increasingly frequent droughts.
Grow north
Currently, 90 percent of European hops comes from southern Germany, the Czech Republic and Slovenia. A possible solution to low yields is to plant plants in the north. Van Ittersum: “In general, we see in many agricultural crop forecasts that northern Europe is performing better than southern Europe, where the weather is already relatively warm and dry. But in order to move forward with hops, we first need to know whether the conditions are Suitable in Northern Europe.
The Czechs themselves may see benefit in planting hops in places with greater shade. New irrigation systems can also provide relief. But according to van Ittersum, more research is needed. “These scientists are skilled at working with models, but experiments with jumps are just as important.”
Brewers will notice the consequences anyway, believes Benjamin Wegmann, founder of Leiden-based brewer Bronk. “Because we produce on a smaller scale, we can switch relatively quickly and adapt our recipe to the hops available. This will be more complex for large-scale brewers.”
Wegman says the development will likely lead to higher prices. “It’s not just the raw materials that are becoming more expensive. If the availability of ingredients changes, we also have to go back to the drawing board more often for a new recipe.
