Drought and high temperatures negatively affect hop crops: they advance their maturation, reduce plant production and the concentration of alpha content (the acid that gives beer its bitter flavor). For this reason, the scientific community predicts that climate change could worsen the quality of beer – in addition to reducing its quantity – if “immediate adaptation measures” are not taken. This is concluded by a study published in the journal Nature Communications, led by Martin Možný, researcher at the Global Change Research Institute of the Czech Academy of Sciences.
The analysis has focused on the reference producing regions in Europe such as Germany, the Czech Republic and Slovenia, countries that cover almost 90% of the total area of ??aromatic hop fields on the continent. The results obtained indicate that, compared to 1994, hop production (a crop that is practically entirely dedicated to brewing beer) has decreased by 0.2 tons per hectare per year.
Furthermore, its ripening has been advanced by an average of 20 days, which negatively affected the alpha content by 0.6%. This last change is what could cause the beer to lose bitterness.
“The specific aroma of hops arises from their bitter acid content; Therefore, changes in alpha bitter acids affect the quality of hops; and there has been a recent variation in consumer preference towards beer aromas and flavors that depend, to a large extent, on these high-quality hops,” the study specifies.
To evaluate the effects of changing weather conditions on hop production and alpha content, scientists simulated non-optimal temperatures and precipitation. High yields and alpha contents were obtained in years in which climatic conditions were close to optimal, while low values ??occurred in years with extreme climatic conditions.
The study estimates that by 2050, due to heat and drought, hop yields could be reduced by up to 31%; and in the case of alpha content, the decrease could reach 18%. In the most optimistic climate scenario (with the greatest reduction in greenhouse gas emissions), the decreases would be 4% and 20%, respectively.
In Germany, the Czech Republic and Slovenia, declines are expected to be more pronounced in the south than in the north of the country. However, the greatest productive impact is estimated to be in Slovenia, Portugal and Spain, where the loss of yield in hop crops due to climate change could reach up to 35%. In all cases, the alpha content drop is expected to be high.
“The critical situation in Spain is derived fundamentally from the lack of water resources and authorized products for the fight and control against diseases or pathogens, causing severe productive losses, as in the current campaign due to powdery mildew (a plant disease). caused by a fungus)”, declares Javier J. Cancela, member of the Project and Planning Research Group (PROePLA) of the University of Santiago de Compostela.
Farmers in different countries have responded to climate change by relocating hop crops to higher altitudes (where temperatures remain lower), building irrigation systems, and even developing more resistant varieties. However, one of the biggest risks regarding climate change posed by the study is that “high-quality aromatic hop crops are restricted to relatively small regions, where environmental conditions are suitable.”
For this reason, and given that it is projected with high confidence that agricultural droughts will increase in southern Europe and with medium confidence, also in central Europe, “it will be necessary to expand the crop area by 20% compared to the area of current production to compensate for a future decline in hop production and alpha content.” This increased likelihood of droughts can also be partially mitigated through less frequent cultivation of hop fields, changes in fertilization, and the use of cover crops to boost root growth.
Cancela argues that there is a need to improve hop varieties worldwide, and emphasizes the case of Spain. The objective would be to increase their level of tolerance to biotic stresses (for example, diseases) and abiotic stresses (droughts and heat waves), “adapting agronomic practices such as irrigation and approving the use of efficient and sustainable phytosanitary products.”
