Formation of brewing qualities of Ukrainian hop varieties under the influence of weather factors

The brewing qualities of hop raw materials are critical in the selection of varieties for beer production. The accumulation of bitter substances, polyphenolic substances and essential oil in hop cones depends on the variety and weather conditions. In this regard, the aim of our research was to scientifically substantiate the proportion of influence of stressful weather factors and varietal characteristics on the process of forming the brewing qualities of hop cones during 2012–2022. For the study, hop cones of 9 varieties of aromatic and bitter types were selected, which were grown in the conditions of hop enterprises in the Zhytomyr region of Ukraine. It was found that in terms of bitter substances content and their variability, the most perspective from the technological point of view were Zagrava (23.0%) and Ruslan (26.1%) varieties with Vp = 8.0–11.7%. The maximum values of alpha-acid content were observed in the same varieties – 5.7% and 9.2%, respectively, with low and medium variability over the years of research (Vp = 8.7–14.0%). The highest stability in the content of polyphenolic substances (Vp = 6.4–8.3%) was found in the varieties Zlato Polissya and Ruslan. The content of essential oil was characterized by high variability (Vp up to 49.4%), the most stable were the varieties Zlato Polissya (Vp = 17.0%) and Ruslan (Vp = 22.8%). It was established that during the study period, the dominant influence on the content of bitter substances, alpha acids and essential oil was exerted by the variety (up to 69.1%), while the content of polyphenolic substances in aromatic hops was determined by weather conditions (34.3%). The results highlight the importance of varietal characteristics in the stability of the biochemical composition of hops in a changing climate. The results are of practical importance for growers and brewers, as well as for hop breeding. Resistant varieties are highly to be used more as a starting material for the creation of new hop varieties that will be more resistant to climate change and provide more stable indicators of brewing qualities of hops.