Hunting for Finnish Hops: Are They Indeed Growing in That North And How Do They Look Like?

Abstract

Hop (Humulus lupulus L.) is dioecious perennial climbing plant belonging to the Cannabaceae family. Female and male hop plants can be also found on the shores and broad-leaved forests on stream banks in Finland. Hop is thought to be originating from East Asia but is also considered native to Finland. Remains of hop pollen were found in the Mesolithic layers in Southern part of the country. Findings of macrofossil seeds date to the Middle Ages and most probably cultivation of hop started then. When Finland was part of Swedish Empire, during the 17th and early 18th centuries, hop inflorescences were used for paying taxes, and there were even legal obligations to cultivate hops until 1915. Hundred years ago there were commercial hop yards in Finland, but unfortunately they have vanished over the years. Since then there have been made several trials to bring hop back to agricultural production, but those attempts did not result in bigger scale cultivation. Now with rising demand for crafts beer the need for local hops is clearer than ever before. For the purpose characterization of hops growing in Finland, we collected samples of 165 different accessions from forests, collections and those ones that presumably had been used in brewing. We analyzed the contents of alpha- and beta-acids and prenylated flavonoids by liquid chromatography (HPLC-DAD), terpenoids by gas chromatography (GC-MS) and for accession with sufficient number of cones also the amount of volatile oils by steam distillation. Genetic analyses were performed with 9 microsatellite markers including also 18 landraces and bred cultivars from Europe. As expected Finnish hops clustered to a separate group easily distinguishable from the European accessions. In the present ongoing project we aim to collect 1000 hops from all over Finland, with the goal of giving image to the polar hop aroma.